Pathology of Cervical Carcinoma

In the past few decades, the epidemiology of cervical cancer has undergone some important changes. In the United States, it is currently the third most common gynecologic cancer following those of the uterine corpus and ovary, with 12,900 new cases and 4100 deaths estimated to have occurred in 2015.¹ While the incidence of cervical cancer has been steadily decreasing in the United States, with an annual percentage change of –2.5% between 1992 and 2011,² the survival rate for cervical cancer has not improved substantially since 1975.¹ Worldwide, there were 527,600 new cases of cervical cancer and 265,700 cervical cancer-related deaths in 2012.³ Incidence and death rates of cervical cancer are particularly high in less developed countries, where it is the second most commonly diagnosed cancer and third leading cause of death in women based on 2012 data.³

Squamous cell carcinoma, which comprised more than 90% of primary cervical cancers before 1960, has decreased steadily in incidence, in large part owing to effective cytologic detection and subsequent eradication of its precursors. The incidence of cervical adenocarcinoma, in contrast, has increased significantly, with a reported 22.5% increase in age-adjusted incidence between 1973 and 1996.⁴

In addition to squamous and glandular neoplasms, neuroendocrine, mesenchymal, and metastatic tumors can also involve the cervix. New techniques in diagnosis have helped to modify histologic classifications. In particular, the use of immunohistochemistry has improved diagnostic accuracy. This chapter deals primarily with cervical malignancies and precursors of squamous and glandular carcinoma. The emphasis is on proper handling and reporting of surgical specimens, pathologic classification and criteria, and important pathologic parameters, all of which have an impact on the prognosis and management of the patient. Finally, recent updates in screening and prevention are discussed.

The accuracy of histologic interpretation and diagnosis is strongly governed by the quality of tissue provided, as well as proper handling and processing of the specimen. In cervical biopsy specimens, many factors lead to unsatisfactory specimens. Distortion and crush artifact usually result from the use of dull or small instruments.⁵ Damage and denudation of the mucosa occur readily even with minor trauma to the cervix. Poor orientation with tangential sections not only precludes accurate interpretation of lesion grade or invasive extent, but also contributes to erroneous diagnoses. Additionally, use of the hemostatic agent Monsel’s solution can cause dark brown discoloration of the tissue, also limiting morphologic interpretation, although an effective destaining technique has been described.⁶ After the tissue is obtained, the specimen should be placed on a piece of paper towel with the mucosal surface upward and the base of the tissue downward. After the blood and mucus at the base of the tissue become adherent to the paper towel, the specimen and the paper towel are placed in buffered formalin and submitted to the laboratory accompanied by adequate demographic and clinical information.

The single most common cause of an inadequate biopsy specimen is the failure to provide abnormal tissue of sufficient amount and depth. Without the underlying stroma, an invasive neoplasm is likely to be interpreted as an in situ lesion. Verrucous squamous carcinoma and papillary, exophytic neoplasms are particularly prone to being underdiagnosed as benign proliferations when the specimen contains only the superficial layers of the neoplasm. Unless the specimen includes the base of the tumor and its underlying stroma, a correct diagnosis may not be made. In mixed tumors (e.g., adenosquamous carcinoma or carcinosarcoma), an inadequate biopsy specimen may not contain both squamous and glandular cellular elements, again resulting in misdiagnosis. Since the earliest squamous intraepithelial lesions occur at the squamocolumnar junction, biopsies from either endocervix or ectocervix only are inadequate for pathologic evaluation. Even in the setting of a negative colposcopic exam, random biopsy of the transformation zone has been demonstrated to be of use in detecting unseen high-grade lesions.⁷

For the treatment of high-grade squamous intraepithelial lesions (HSIL)/cervical intraepithelial neoplasia (CIN), cervical tissue removed by loop electrosurgical excision procedure (LEEP) has become widely accepted. The pathologist usually receives tissue from the anterior lip and the posterior lip, either separately or as a single circumferential portion of cervix. A third disc-shaped tissue fragment from the base of the excision or endocervical margin is sometimes received (“top hat”), and a post-LEEP endocervical curettage (ECC) is usually also received. Diagnostic problems in these specimens are most often caused by a lack of orientation and thermal damage. The specimen should be oriented by a suture or ink to indicate 12 o'clock. This allows sectioning radially around the endocervical canal. Without orientation, the specimen may be cut erroneously and the lesion may be missed entirely. Excessive maneuvers by the surgeon or pathologist lead to extensive denudation and loss of the cervical mucosa and potentially the lesion. Prolonged contact between the loop and the tissue results in broad zones of thermal damage, coagulative necrosis, and tissue distortion that preclude an accurate diagnosis of the lesion and the status of excision margins. In one study, 20% of ectocervical margins and 44% of endocervical margins removed by LEEP were unsatisfactory for evaluation.⁸ The use of the immunohistochemical stain p16 (see below) can help with assessment of excessively distorted and cauterized margins. With proper surgical technique, orientation of the specimen, marking of the margins by the surgeon, and appropriate use of immunohistochemistry, most LEEP specimens are reported to be adequate for interpretation. The status of excision margins correlates well with the subsequent recurrence of SIL/CIN.⁹

Cervical conization by cold knife is most often performed for extensive HSIL and for HSIL with suspected coexisting invasive carcinoma. If the cervical biopsy specimen or endocervical curettage specimen suggests the possibility of endocervical adenocarcinoma in situ, cervical conization is often used to confirm the diagnosis, excise the lesion, and exclude coexisting invasive adenocarcinoma.

Cervical conization specimens should be oriented by placing a suture at 12 o'clock, and should be submitted to the laboratory in the fresh state. After opening at 12 o'clock along the cervical canal, the specimen is pinned out on a cork board, immersed in fixative, and subsequently radially sectioned in a clockwise fashion. This method of sectioning provides perpendicular cuts through the mucosa and wall allowing for accurate determination of the disease process and its extent, depth, and relation to the surgical margins.⁵ An already fixed specimen may be too rigid for opening and pinning out.

In radical hysterectomy specimens, representative sections should include the most advanced area of tumor to determine the maximal stromal invasion. All surgical margins should be carefully identified and marked with ink. The parametrium needs special attention, as involvement of this area by the tumor has important clinical implications. 

Pelvic lymph nodes should be properly labeled as to their anatomic sites. Benign Müllerian inclusions (endosalpingiosis) and decidual cells are known to occur in the peritoneum and in pelvic and paraaortic lymph nodes. Without knowledge of a pregnancy history, decidual cells in lymph nodes and pelvis may be misclassified as metastatic carcinoma cells. Serial sectioning of lymph nodes at 3 mm intervals may increase detection of small metastastic foci. Similarly, tissue reactions to prior surgery, radiation, and complications, such as intestinal perforation, can be difficult to separate from malignant tumor, especially on frozen sections. Thus, an accurate pathologic interpretation requires a close collaboration, communication, and understanding between the clinician and the pathologist.

In any cervical excision, the pathology report should include the following:

• Specimen/procedure type
• Tumor size
• Histologic type and grade
• Depth of stromal invasion
• Status of surgical margins
  • For LEEP or cone specimens: endocervical, ectocervical, and deep margins
  • For hysterectomy specimens: vaginal/ectocervical, deep/paracervical, and lateral/parametrial margins
• The presence or absence of lymph-vascular space invasion.

Involvement of endometrium should be noted, although its presence does not alter the FIGO stage. All pelvic and paraaortic lymph nodes received should be embedded and carefully studied, sometimes by multiple levels as indicated by institutional guidelines.

The ectocervix is covered by mature squamous mucosa, whereas the endocervix is lined by mucus-secreting endocervical epithelium. The latter undergoes squamous metaplasia through both reserve cell hyperplasia (true squamous metaplasia) as well as squamous epithelialization (direct ingrowth of existing squamous epithelium). In addition, metaplastic glandular cells (ciliated tubal, tuboendometrioid, oxyphilic) and mesonephric remnants occur in the endocervix. Rare neuroectodermal cells (argyrophilic, neuroendocrine, melanocytic cells) also exist in the normal cervix. These epithelial and neuroectodermal cells are potential progenitors or components of cervical carcinoma. Cervical stromal cells may rarely become neoplastic, presenting as a pure mesodermal tumor or mixed with an epithelial neoplasm.

Most cervical squamous cell carcinomas likely originate from the metaplastic squamous epithelium located between the original and new squamocolumnar junctions, the transformation zone. Adenocarcinomas typically occur within the endocervical canal. Recent studies have demonstrated evidence that carcinogenic HPV-related squamous intraepithelial lesions and cervical cancers are linked to a small, discrete cell population of cells that localizes to the squamocolumnar (SC) junction of the cervix.¹⁰

Clinical and pathologic data support the concept that most invasive carcinomas develop from a preneoplastic intraepithelial lesion. Although many aspects of the cause of cervical cancer remain to be determined, human papillomavirus (HPV), particularly high-risk types (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, and 82),¹¹ has been identified in squamous, glandular, and other less common types of cervical neoplasms. HPV infection is believed to play an important role at least as an initiator of cervical neoplasia (see below for additional discussion).

Carcinoma of the cervix may have a variety of clinical presentations. It may be discovered on routine Papanicolaou (Pap) smear in an asymptomatic woman; patients may present with irregular vaginal bleeding; or, in late stages, patients may present with symptoms of a mass lesion or metastatic disease. The cervix with early carcinoma has a poorly circumscribed granular or eroded appearance and bleeds easily on contact. At later stages, nodular, ulcerated lesions or an exophytic mass appear. Endophytic growth occurs in the cervical canal with direct infiltration into the wall causing diffuse enlargement and hardening of the cervix. The mucosal surface may be covered by normal epithelium, and the underlying malignant cells may escape detection by cytologic smear. Some cervical carcinomas are located in the cervical canal and grow endophytically without causing gross abnormality. When the cervix is diffusely enlarged, bulky, and larger than 6 cm in size, it is referred to as a barrel-shaped cervix. This gross appearance can be seen in any tumor type, although it is most commonly associated with adenocarcinoma.

Local extension of cervical carcinoma proceeds in a predictable manner to involve the endometrium superiorly and the upper vagina inferiorly. Parametrial involvement results from extension through the cervical stroma or lymph-vascular space invasion. From the parametrium the tumor may extend laterally to the pelvic sidewall, anteriorly to the bladder base, or posteriorly to the rectum. An unusual pattern of local spread is in the form of carcinoma in situ extending to the endometrium and/or fallopian tubes.

The International Federation of Gynecologists and Obstetricians (FIGO) updated their clinical staging system in 2009, taking into account the issues of surgical vs. clinical staging, early invasion amenable to more conservative treatment, and the utility of additional substages, among other considerations.^{12, 13} The current staging guidelines are outlined below (Table 1).

 

Table 1. Definition of FIGO clinical staging for cervical cancer

Adapted from FIGO staging for carcinoma of the vulva, cervix, and corpus uteri. FIGO Committee on Gynecologic Oncology. Int J Gynaecol Obstet 2014;125(2):97-8.¹⁴

Cervical intraepithelial neoplasia (CIN) is a relatively common problem, especially in women of reproductive age. Laboratory surveys from the mid-1990s from the College of American Pathologists suggest that more than 1 million women are diagnosed each year with low-grade cervical intraepithelial lesions and that approximately 500,000 are diagnosed with high-grade cervical cancer precursor lesions.¹⁵

Of the more than 150 HPV types known to exist, only about 15 types of HPV viruses are known to increase the risk of cervical cancer. High risk (carcinogenic) types of HPV include HPV 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 73, and 82. Of these, types 16, 18, 45, 31, 33, 52, 58, and 35 account for over 95% of cervical squamous cell carcinomas, with types 16 and 18 associated with the greatest risk of carcinoma.¹¹ The most common low-risk HPV types are HPV 6 and 11, infection with which usually results in low-grade, non-preneoplastic lesions.  

In recent years, an increased understanding of HPV biology has modified our understanding of cervical carcinogenesis and the significance of different grades of precursor lesions. Traditionally, cervical intraepithelial lesions have been classified using a three-tiered system (originally mild/moderate/severe dysplasia, subsequently CIN 1/2/3), corresponding to a presumed stepwise progression from low to intermediate to high-grade intraepithelial lesions, followed by invasive carcinoma. Additionally, some pathologists favor employing two additional tiers of HPV-related intraepithelial lesions: “HPV effect”/“koilocytic atypia”/“flat condyloma,” corresponding to viral cytopathic effect sans dysplasia, and “carcinoma in situ,” corresponding to full thickness dysplasia. However, it appears that the interaction between HPV and the cervical epithelium is actually dichotomous. Infection of the cervical epithelium may result in either transient productive infection with viral proliferation, or in persistent infection with progression to precancer. The latter is mediated primarily by two viral proteins, E6 and E7.

The early viral protein E6 binds to p53 protein in the host epithelial cell, resulting in its degradation and loss of its normal functions promoting growth arrest and apoptosis. The early viral protein E7 binds to pRb protein in the host epithelial cell, resulting in release of the DNA replication-promoting transcription factor E2F. In high-risk HPV types, the E6 and E7 proteins have greater affinity for host p53 and pRb, respectively. Disruption of the early viral protein E2 by viral integration into the host genome also plays a role in cell cycle disruption by causing increased expression of E6 and E7.^{16, 17}

In order to better align diagnostic terminology with the current understanding of HPV biology, a multidisciplinary consensus effort was undertaken in 2012 to standardize diagnosis and terminology for HPV-related squamous lesions of all lower anogenital tract sites. This initiative was termed the Lower Anogenital Squamous Terminology (LAST) project, and was co-sponsored by the College of American Pathologists (CAP) and the American Society for Colposcopy and Cervical Pathology (ASCCP).¹⁸ One of the resulting consensus guidelines was switching to a two-tiered nomenclature for HPV-related lesions of the lower anogenital tract. Specifically, the authors recommended use of the terms “low-grade squamous intraepithelial lesion” (LSIL) and “high-grade squamous intraepithelial lesion” (HSIL). These terms had previously been used only for cytology interpretation under the Bethesda system. Histologic LSIL corresponds to CIN 1, including both lesions with loss of maturation in the lower third of the epithelium (mild dysplasia) and those with HPV cytopathic effect without dysplasia. Histologic HSIL corresponds to CIN 2 and CIN 3, and includes the spectrum from moderate dysplasia to carcinoma in situ.¹⁸

Justification for these new guidelines is multifold. Firstly, a dichotomous terminology better corresponds to the dichotomous biology of HPV infection. Secondly, switching to a two-tiered system improves diagnostic reproducibility.^{19, 20, 21, 22} In particular, CIN 2 has been demonstrated to have especially poor reproducibility, and no unique biology of CIN 2 vs. CIN 1 and 3 has been elucidated. The authors of the LAST project suggest that CIN 2 in fact consists of an admixture of CIN 1 and CIN 3 which cannot be accurately distinguished on morphology.¹⁸

In order to provide a smoother transition to the new system of nomenclature, as well as to allow for conservative management of young women with CIN 2 (which has a higher regression rate than lesions diagnosed as CIN 3), the LAST project guidelines recommend use of LSIL/HSIL terminology with parenthetical use of the older terminology (e.g. “High-grade squamous intraepithelial lesion (CIN 2)”). This practice will allow clinicians to continue to have the option for more conservative management of this lesion in younger patients.

The diagnosis of HSIL/CIN 2 in particular is also subject to certain caveats as per the LAST project guidelines, specifically the requirement for confirmation using p16 immunohistochemistry (discussed in more detail below).

Low-grade squamous intraepithelial lesion

Low-grade squamous intraepithelial lesion (LSIL) in the cervix is most commonly flat, but may rarely be exophytic (Fig. 1). Flat LSIL is characterized by dysplasia in the lower one third of the epithelium and/or HPV cytopathic effect. Condyloma acuminatum is an exophytic papillary lesion with viral cytopathic effect but no significant dysplasia. Although the LAST guidelines recommend classifying condyloma acuminatum as LSIL, with an optional parenthetical qualifier, an argument can be made that it is important to distinguish condyloma acuminatum from flat LSIL. Whereas up to 80% of flat LSIL is related to high-risk HPV,²³ condyloma acuminatum is essentially always associated with the low-risk HPV types 6 and 11, with almost no risk for progression without co-infection with other HPV types.^{24, 25} Flat LSIL regresses in 57% of cases, persists in 32%, and progresses to HSIL or invasive carcinoma in 12%.²⁶ It should be noted, however, that current management guidelines do not distinguish between these two lesions for the purposes of follow-up and treatment.

The typical cytopathic effect of HPV on squamous epithelial cells can be diagnosed by the presence of demarcated cytoplasmic clearing (“halos”), large, coarse and hyperchromatic nuclei, nuclear membrane irregularity (“raisinoid” nuclei), and bi- or multinucleation. Similar changes can be seen with reactive epithelial change in the setting of inflammation, as well as with degenerative change as is frequently encountered in detached epithelial fragments in cervical biopsy and endocervical curettage specimens. Careful assessment for typical cytologic features and for the presence of potentially confounding factors should therefore be undertaken.

Fig. 1. Low-grade squamous intraepithelial lesion (LSIL). (A) Condyloma acuminatum shows papillomatosis, acanthosis, parakeratosis, and hyperkeratosis. Each papillary frond has a tiny blood vessel at its core. (B) Flat LSIL has koilocytotic atypia (bi/multinucleation, irregular nuclear contours, nuclear enlargement and hyperchromasia, and cytoplasmic clearing [halos]). Dysplasia may be present in up to the lower one third of the epithelium. (Hematoxylin-eosin stain, red bar: original magnification.)

 

High-grade squamous intraepithelial lesion

High-grade squamous intraepithelial lesion (HSIL) is a precancerous lesion characterized by an abnormal parabasal-like cell proliferation with loss of polarity, overlapping nuclei, high nuclear-to-cytoplasmic ratio, increased mitoses, dyskeratosis, apoptosis, hyperchromasia, and significant nuclear atypia. Viral cytopathic effect may or may not be present. The immature and atypical epithelium extends to at least the middle third of the epithelium and may involve up to the full thickness of the epithelium. 

HSIL encompasses both CIN 2 (dysplasia involving the lower two thirds of the epithelium) and CIN 3 (dysplasia extending to the upper third of the epithelium) (Fig. 2). Though both are considered preneoplastic lesions with a risk for progression, the rates of regression, persistence, and progression differ for these two lesion grades. Compared to CIN 3, CIN 2 regresses more frequently (43% vs. 32%), persists less frequently (35% vs. 56%), and progresses to invasive carcinoma less frequently (5% vs. 12%).²⁶ Because CIN 2 is considered to be a somewhat ambiguous diagnostic entity without a biologic correlate, the LAST guidelines recommend use of ancillary testing to confirm the diagnosis of HSIL. Specifically, the authors of LAST recommend performing an immunohistochemical stain for p16 (see biomarker discussion below) to confirm the diagnosis of HSIL when the morphology is consistent with CIN 2, as well as to adjudicate CIN 1 vs. CIN 2 diagnostic uncertainty. Diffuse, strong, block positivity for p16 in at least the lower third of the epithelium supports the diagnosis of HSIL, while all other staining patterns (negative, focal, patchy) favor a diagnosis of LSIL or less (Fig. 3).¹⁸ It should be noted, however, that approximately half of LSILs will express diffuse block p16 positivity^{27, 28, 29} (correlating with high-risk HPV),³⁰ and therefore it is important that the morphologic features also support a diagnosis of HSIL. If p16 immunostaining is not readily available, morphologic subclassification of HSIL (CIN 2 vs. 3) and characterization of the extent of the lesion may be helpful for patient management.

 

Fig. 2. High-grade squamous intraepithelial lesion (HSIL). (A) CIN 2: Dysplastic squamous cells in the basal two-thirds of the epithelium; the upper half of the epithelium shows koilocytic atypia; (B) CIN 3: Dysplastic squamous cells present throughout the full thickness of the epithelium; koilocytic atypia is present in the superficial layers. (Hematoxylin-eosin stain)

 

 

 

Fig. 3. p16 immunohistochemistry. (A) Diffuse strong p16 expression in area of atypical attenuated squamous epithelium, supporting diagnosis of HSIL. (Hematoxylin-eosin stain, red bar: original magnification) (B) Patchy p16 expression in area of atypical squamous epithelium, arguing against diagnosis of HSIL.

 

 

In contrast to LSIL, true in situ neoplasia is a monoclonal proliferations of cells that show evidence of genetic instability.³¹ The majority of such lesions are aneuploid and have loss of heterozygosity at nonrandom chromosomal loci that may be associated with neoplastic development.³² HSIL also has much less heterogeneity with respect to associated HPV types than do CIN 1 lesions.³¹

Current management guidelines from the ASCCP recommend excision of HSIL (CIN 2 or 3) in most women. However, in young women aged 21–24 years with CIN 2 specifically, observation is preferred.³³

Biomarkers in the diagnosis of squamous intraepithelial lesions

Numerous biomarkers have been investigated for their potential utility in the diagnosis of cervical squamous intraepithelial lesions. These include p16^ink4, Ki-67 (MIB-1), ProEx C, high-risk HPV, the late viral proteins L1 and L2, and telomerase. The discussion below focuses on p16 and Ki-67, the most widely used in clinical practice.

p16

The tumor suppressor gene CDKN2a encodes the protein p16^ink4 (p16), a cyclin-dependent kinase inhibitor which promotes arrest of the cell cycle.³⁴ Specifically, p16 inactivates cdk4-Cyclin D1 and cdk6-Cyclin D1 complexes, which normally phosphorylate pRb and cause it to release a transcription factor (E2F) which promotes transition of the cell into S phase. Due to the inverse relationship between p16 and pRb, binding of the viral protein E7 to the host cell pRb results in increased expression of p16.³⁴ This inverse relationship allows p16 expression to be a convenient marker of high-risk HPV infection with cell cycle disruption.³⁵ Immunohistochemical expression of p16 has been correlated with high-risk HPV and with increasing degree of dysplasia.^{23, 30, 36, 37, 38, 39, 40}

Positivity for p16, defined as strong diffuse block positivity in at least the lower third of the epithelium, is present in the vast majority of HSILs (81.1–100% of CIN 2 and 100% of CIN 3) and a subset of LSILs (39–53%).^{28, 29, 35, 41} Therefore, while p16 is an excellent marker for the distinction of HSIL from benign mimics, it is not useful for LSIL vs. benign mimics. Additionally, given the expression of p16 in a significant percentage of LSILs, some caution is necessary in adhering to the new guidelines recommending use of p16 to adjudicate CIN 1 vs. CIN 2 diagnostic uncertainty, and some authors disagree with the use of p16 in this setting due to the risk of overdiagnosis and overtreatment of LSIL.

The use of p16 increases interobserver agreement and individual pathologist accuracy.^{29, 42, 43, 44, 45} It has also been demonstrated to be useful in identifying subtle foci of HSIL which were not initially identified on routine hematoxylin-and-eosin (H&E)-stained sections, and thus may be a useful screening tool in certain high risk scenarios (see below).^{29, 46}

The potential prognostic significance of p16 has also been investigated, particularly for LSIL, in which it may predict a greater likelihood of progression and lesser likelihood of regression.^{47, 48, 49, 50, 51, 52} The data are, however, as yet insufficiently compelling to apply to clinical practice. Studies on CIN 2 and p16 as a predictor of progression are fewer, with somewhat inconsistent results, but there is some evidence that p16 may be a predictor of subsequent definitive HSIL.^{53, 54, 55, 56, 57, 58}

The authors of the LAST project reviewed several biomarkers, and found sufficient evidence to make a recommendation only for p16. The guidelines recommend use of p16 in the following scenarios:¹⁸

• Distinguishing HSIL from benign mimics (e.g. atrophy, reactive change, tangential sectioning, immature metaplasia)
• Confirming the morphologic impression or consideration of CIN 2
• Adjudicating professional disagreement when HSIL is in the differential diagnosis
• Screening for subtle foci of HSIL in a biopsy specimen with CIN 1 or less, in the setting of a prior cytology diagnosis conferring a high risk for HSIL [specifically: HSIL, atypical squamous cells of uncertain significance (ASC-US)/HPV 16+, atypical squamous cells, cannot rule out HSIL (ASC-H), and atypical glandular cells, not otherwise specified (AGC NOS)].

Ki-67

The other frequently used immunohistochemical marker in the diagnosis of cervical intraepithelial lesions is Ki-67, a nuclear nonhistone protein which serves as a marker of cell proliferation.⁴⁰ Typically, normal and metaplastic squamous epithelium expresses Ki-67 only in the parabasal cell layer, while it extends to the intermediate cell layers in LSIL, and is present in all layers in HSIL.⁵⁹ However, increased expression of Ki-67 is not specific, as reactive and inflamed epithelium can also have an increased proliferation index.³⁸ Additionally, some studies have found p16 staining to be more specific than Ki-67 for HSIL, without significant added utility of Ki-67 in conjunction with p16.²⁷ While Ki-67 can have some utility in distinguishing HPV-related intraepithelial lesions from non-HPV-related lesions, it is less useful for distinguishing LSIL from HSIL.

High-risk HPV

Testing for high-risk HPV is currently performed on cervical cytology specimens as a primary screening test, as part of co-testing for women >30 years of age, and as a reflex test following an abnormal cytologic diagnosis.^{33, 60, 61} The use of genotyping assays is increasing, as it has been demonstrated that the presence of HPV 16 or 18 in the setting of ASCUS is associated with a significantly higher risk of HSIL than are other high-risk HPV types.⁶² On tissue sections, in situ hybridization (ISH) for different HPV types can be performed. While the mere presence of high-risk HPV would not be useful in grading lesions (although this can be used to confirm diagnosis of an HPV-related lesion vs. a non-HPV-related lesion), the presence of punctate rather than diffuse signal has been demonstrated to correlate with viral integration into the host cell genome.^{23, 63, 64} While this could theoretically be used to assist with grading lesions, the utility is limited by some variability in integration and signal type data, as well as issues with sensitivity compared with polymerase chain reaction (PCR) and p16.^{65, 66, 67, 68, 69}

ProEx C

ProEx C targets topoisomerase II-alpha and minichromosome maintenance protein-2. The immunostain demonstrates an expression pattern that is similar to Ki-67,^{70, 71} and expression of ProEx C correlates with p16 and high-risk HPV positivity.^{40, 71, 72} Similar to p16, the utility of this marker seems to be in distinguishing HSIL from benign mimics, but limited for determining LSIL vs. HSIL, and the data are much less abundant than for p16.

L1 and L2

The late viral proteins L1 and L2 encode capsid proteins and are expressed only in terminally differentiated squamous cells.⁷³ The expression of L1 is inversely correlated with lesion grade, and there is some evidence that absence of L1 may also predict progression or unsampled concurrent higher grade lesions.^{73, 74, 75, 76, 77} A similar inverse relationship with lesion grade has been described for L2, although the data are fewer.⁷⁸ Currently, the data for both markers is insufficient for incorporation into routine practice.

Superficially invasive squamous cell carcinoma (SISCC)

This entity, previously called microinvasive carcinoma, was first described in 1847 as a squamous cell carcinoma of the cervix with ≤5 mm of invasion into the stroma.⁷⁹ Since that time, various other terms and definitions have been employed, making “microinvasion” a somewhat confusing entity. For example, the Society of Gynecologic Oncologists defined microinvasive carcinoma of the cervix in 1973 as having a maximum depth of invasion of 3 mm, with the additional requirement of having no lymph-vascular space invasion.⁸⁰ Also relevant to the definition of microinvasion is the evolution of the FIGO staging system for carcinoma of the cervix. The definition of FIGO stage IA carcinomas was refined in 1994, with stage IA1 defined as having a maximum depth of invasion of 3 mm a maximum horizontal extent of 7 mm, and stage IA2 defined as having a maximum depth of invasion between 3 and 5 mm and again a maximum horizontal extent of 7 mm.⁸¹ The 2009 revision of cervical cancer staging from FIGO retained these definitions.¹³

The importance of a consistent definition for microinvasive carcinoma in the cervix is its ability to identify patients who may be managed effectively with more conservative treatment. Specifically, it has been demonstrated that patients with microinvasive cervical carcinoma can be treated with LEEP, cold knife conization, or simple (rather than radical) hysterectomy, while still having a low risk of lymph node metastases and recurrence.^{80, 82, 83, 84, 85, 86, 87, 88, 89} Sources of controversy in the definition over the decades have related to the specific depth of invasion allowed, the need for a horizontal size cut-off, whether the absence of lymph-vascular space invasion should be required, and the significance of positive margins (for either invasive or intraepithelial lesions). It has been demonstrated that a depth of invasion of 5 mm or less confers a low risk of death or metastasis (1.2%), with some reporting that the specific depth less than 5 mm does not provide additional prognostic value.^{90, 91, 92} However, others have been able to demonstrate that a depth of invasion between 3 and 5 mm confers a higher risk of metastasis, recurrence, and death than a depth of invasion 3 mm or less.^{85, 87, 93, 94, 95, 96} These later data are reflected in the current FIGO staging system, with its subdivision of stage IA carcinomas as IA1 and IA2.

Given the historic controversy and inconsistency in the definition of microinvasion, the LAST project included in its guidelines updated and standardized definitions for this entity in each lower anogenital tract site. In order to avoid confusion with the various prior definitions of microinvasion, the authors proposed switching to the new terminology of “superficially invasive squamous cell carcinoma” (SISCC).¹⁸ In the cervix, SISCC was defined as a FIGO stage IA1 carcinoma, corresponding to a microscopic lesion measuring no more than 3 mm in depth and no more than 7 mm in horizontal extent (Fig. 4). Although the presence of lymph-vascular space invasion (which may increase the risk of lymph node metastasis and recurrence)^{85, 94, 95} as well as the presence of intraepithelial lesions at the margin (which increases the risk of recurrence and residual disease)^{97, 98, 99, 100, 101, 102, 103, 104, 105} should be reported, the absence of these features is not required to render a diagnosis of SISCC.¹⁸ While the invasive component must be completely excised to render a definitive diagnosis of SISCC, invasive carcinomas within the size cut-offs but extending to margins can be diagnosed as “at least superficially invasive squamous cell carcinoma” with a comment regarding positive margins.

 

Fig. 4. Superficially invasive squamous cell carcinoma. HSIL with budding off of malignant cells downward into the underlying stroma and significant associated lymphocytic infiltrate. (Hematoxylin-eosin stain, yellow bars: original magnification.)

 

 

 

 

Invasive squamous cell carcinoma

Squamous cell carcinoma (SCC) is by far the most common tumor of the cervix. While the incidence of SCC has declined in the United States over the last few decades (approximately 40% between 1973 and 1996), it continues to account for 70–80% of cervical carcinomas in the United States,⁴ and the worldwide incidence of SCC is in fact increasing.¹⁰⁶ SCC most commonly affects women in their mid-30s to mid-40s, but can affect women over a wide age range, from <20 to >80 years of age. The vast majority of these tumors (>99% worldwide) are related to infection with HPV.¹⁰⁸

Microscopically, invasive SCC is characterized by infiltrating nests of neoplastic squamous epithelium in the stroma. These nests typically display an irregular, angulated shape, and may demonstrate increased cytoplasmic keratinization (so-called paradoxical maturation). Both of these features help distinguish true invasion from HSIL extending into endocervical glands (which is still considered an in situ process).

Various subtypes of cervical SCC have been described. In 1958 Wentz and Reagan¹⁰⁹ divided cervical SCC into three cell types: large cell keratinizing, large cell nonkeratinizing, and small cell. With the advent of electron microscopy and immunohistochemistry, it became apparent that what had been termed small cell SCC really represents a heterogeneous group of tumors, including basaloid SCC and small cell neuroendocrine carcinoma. The current WHO subclassification of SCC is as follows:

• Keratinizing
• Non-keratinizing
• Basaloid
• Warty
• Papillary
• Verrucous
• Squamotransitional
• Lymphoepithelioma-like

These subtypes are discussed in greater detail below.

The value of separating SCC by subtypes was evaluated using data from the Gynecologic Oncology Group (GOG). Among women with stage I SCC treated surgically, the subtype was not predictive of pelvic nodal metastasis or outcome.^{110, 111} The percentages of patients who were progression-free at 5 years were 84% for large cell keratinizing SCC and 74% for large cell nonkeratinizing SCC, a difference which was not statistically significant. The differences among different grades were also not statistically significant, with the following percentages of patients who were progression-free at 5 years: 75% for grade 1, 82% for grade 2, and 78% for grade 3.¹¹⁰ However, the consistency and reproducibility among pathologists in separating keratinizing and nonkeratinizing tumors based on cervical biopsy specimens may have caused some problems in interpretation. In a GOG study of women with stage IIB–IVA SCC treated by radiation therapy, when the histologic criteria were modified to include all tumors with individual cell keratinization in the large cell keratinizing category, this group had a significantly higher recurrence/death rate than the large cell nonkeratinizing group (65.8% vs 53.5%, p = 0.0074).¹¹²

Keratinizing SCC

Keratinizing SCC is characterized by well-differentiated squamous cells infiltrating as nests, cords, and sheets of cells (Fig. 5). The cells have abundant cytoplasm, large pleomorphic nuclei, and inconspicuous nucleoli. Keratin pearls and intercellular bridges are evident. Mitotic figures are noted occasionally but are not typically numerous. The presence of even one keratin pearl has been considered sufficient for diagnosis. Keratin pearls are circular whorls of squamous epithelium with central nests of acellular keratin. Keratohyaline granules and individual cell keratinization are also seen.

 

Fig. 5. Squamous cell carcinoma of the cervix, keratinizing type. Malignant squamous cells form irregular nests invading the stroma. In the center of the nest, laminated keratin pearls are present. Individual cells have abundant eosinophilic keratinized cytoplasm. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

Non-keratinizing SCC

Non-keratinizing SCC is characterized by large cells of similar size and shape with indistinct cell borders, infiltrating as nests and sheets (Fig. 6). The cytoplasm is moderate in amount and eosinophilic to amphophilic. Individual cell keratinization may be seen, but keratin pearl formation should be absent. Nucleoli are prominent and mitotic figures are common.

 

Fig. 6. Squamous cell carcinoma of the cervix, non-keratinizing type. Malignant squamous cells have abundant eosinophilic cytoplasm, distinct cell borders, and individual cell keratinization. The irregular, large nuclei contain multiple nucleoli. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

Basaloid SCC

Basaloid SCC (previously called small cell nonkeratinizing SCC) is an aggressive variant characterized by loosely cohesive nests and sheets of small to medium sized cells with hyperchromatic nuclei, scant cytoplasm, and small nucleoli. Keratinization is minimal or absent, and mitotic figures are abundant. The nuclear chromatin is finely to coarsely granular, and small nucleoli are often evident (Fig. 7). Crush artifact and nuclear smudging are not prominent. The nuclear-to-cytoplasmic ratio is lower than in small cell neuroendocrine carcinoma. The cell borders are also more distinct. Rare cytoplasmic keratinization may be present, allowing recognition of the squamous nature of the lesion. Necrosis is frequently observed.

 

Fig. 7. Squamous cell carcinoma of the cervix, basaloid type. The malignant squamous cells have small round to oval nuclei, finely granular chromatin, and small nucleoli. Most of the tumor cells contain a small amount of eosinophilic cytoplasm. Mitotic figures are abundant. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

Warty SCC

Warty or condylomatous SCC demonstrates low-power architecture very similar to condyloma acuminatum. Cytologic features of koilocytosis are present. The deep edge of the tumor, however, displays features more consistent with conventional SCC, distinguishing these from verrucous carcinoma. This variant may be less aggressive than conventional well-differentiated SCC.¹¹³

Papillary SCC and squamotransitional carcinoma

Papillary SCC of the cervix is characterized by highly dysplastic squamous cells forming papillary fronds with thin to broad fibrovascular cores. Not surprisingly, the gross appearance of this lesion may be warty or fungating as in verrucous squamous carcinoma. Some papillary carcinomas of the cervix demonstrate features similar to transitional cell carcinoma of the urothelial tract, and terms such as papillary squamotransitional cell carcinoma and transitional cell carcinoma have been used.^{114, 115} Despite the morphologic resemblance to poorly differentiated transitional cell carcinoma of the urinary bladder, these tumors all display a similar immunohistochemical profile, with one study finding only two of 21 (9.5%) tumors expressing cytokeratin 20 (a marker supporting urothelial over squamous differentiation).¹¹⁴ Therefore, it is favored that these represent squamous cell carcinomas with a spectrum of morphologic appearances.

In a series of 32 women, the age of patients with papillary squamous cell carcinoma varied from 22 to 93 years (mean 50 years).¹¹⁴ The women presented with abnormal bleeding or abnormal cervical smears. The tumor size ranged from 0.7 to 6 cm (mean 3.0 cm). The usual diagnostic problem associated with this diagnosis is evident in the fact that only 20 of 32 (63%) specimens were considered to be adequate. The remaining 37% were too superficial to determine whether they were in situ or invasive carcinoma. Of those with suitable specimens, 90% (18 of 20) had stromal invasion.¹¹⁴ In another study, one tumor was found to be an in situ lesion, whereas the remaining eight cases ranged from stage I to stage IV invasive carcinoma.¹¹⁶ Since invasion is evident only in the stroma beneath the papillary surface components, deep biopsy specimens are necessary to distinguish in situ from invasive lesions. This is particularly important given that papillary SCC can behave aggressively with metastasis and recurrence.^{114, 116}

Verrucous carcinoma

Verrucous carcinoma of the cervix, like that of other sites, represents a special variant of well-differentiated squamous carcinoma. Grossly, these tumors appear exophytic and warty, and may simulate a condyloma acuminatum. Histologically, the cells show orderly maturation and lack cytologic atypia. The tumor grows by expansion with smooth, pushing borders, as opposed to the infiltrating pattern of conventional SCC. To differentiate verrucous carcinoma from condyloma, pseudoepitheliomatous hyperplasia, or typical SCC, deep biopsy specimens are necessary. Some conventional SCCs have a verrucous appearance superficially but show severe nuclear atypia and foci of invasion by nests or single cells in the stroma. These tumors behave like conventional SCC and should be classified as such. Condyloma acuminatum has prominent koilocytosis and delicate fibrovascular cores, as opposed to the compressed cores and confluent epithelial growth pattern seen in verrucous carcinoma. Condylomata also lack the expansile, endophytic extension into the stroma seen in verrucous carcinomas.

Verrucous carcinomas can be deeply invasive and cases extending into the vagina and endometrium have been described. Local recurrence is common, but lymph node and distant metastases are rare.^{113, 117}

Lymphoepithelioma-like carcinoma

Circumscribed carcinoma of the uterine cervix was described in 1977 by Hasumi and associates.¹¹⁸ In their study, the tumors were characterized by solid cords of cells with neither squamous nor glandular differentiation, surrounded by a dense lymphocytic infiltrate, which occasionally contained a considerable number of eosinophils and plasma cells. The tumor cells were fairly monomorphic, with large nuclei, one or more nucleoli, and clear to eosinophilic, granular cytoplasm. Many mitotic figures were seen. All 39 cases reported measured larger than 5 mm in depth, but only two (5%) had lymph node metastases at the time of surgery, compared with 18% of ordinary squamous carcinomas of comparable stage. Improved 5-year survival was also seen in these cases (97% vs. 79%, p <0.05).¹¹⁸

Studies of similar, if not identical, tumors use the term lymphoepithelioma-like carcinoma to indicate the histologic likeness to the lymphoepithelioma of the nasopharynx and the malignant lymphoepithelial lesions of the salivary glands.^{119, 120} In a study by Tseng and associates,¹²¹ 15 such tumors were compared with conventional SCC by PCR. Epstein-Barr viral gene sequences were found in 11 of 15 tumors (73%), compared with four of 15 (27%) of the usual SCC (p = 0.001). Interestingly, HPV 16 and 18 types were detected in 20% (three of 15) of these tumors, compared with 80% (12 of 15) of the usual SCC (p = 0.001).¹²¹

Although the total number of cases in the literature is too small for complete understanding of these neoplasms, they appear to have a better prognosis than conventional SCC. After radical hysterectomy, all 15 patients in one study were alive and well.¹²¹

Spindle cell SCC

Although not part of the current WHO classification system, a spindled variant of SCC is also recognized. Spindle cell SCC is a rare variant of poorly differentiated SCC that may be confused with either melanoma or sarcoma.^{5, 122} This tumor is composed of cells with large, spindle shaped or oblong nuclei arranged in fascicles (Fig. 8). Keratin formation and the nesting pattern typical of epithelial tumors may be absent. Stromal changes such as heavy collagen deposition may give the appearance of a fibrosarcoma or osteosarcoma. When confronted with such a lesion, immunohistochemistry is often required to identify the epithelial nature. Positive immunohistochemical stains for epithelial markers (e.g. cytokeratin) favor the diagnosis of a spindle cell SCC over a mesenchymal tumor.

 

Fig. 8. Squamous cell carcinoma of the cervix, spindle cell type. Elongated tumor cells are arranged in bundles simulating spindle cell sarcoma. Immunohistochemical stain for cytokeratin was positive, confirming the diagnosis of carcinoma (not shown). (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

One may also rarely see abnormal spindle cells in the cervical stroma adjacent to typical SCC. This so called pseudosarcoma was reported by Watty and colleagues,¹²³ who described individual atypical stromal cells with elongated, pleomorphic nuclei and frequent multinucleation. Rare abnormal mitotic figures were seen. The authors felt that this change represented a response to the nearby tumor and noted that similar lesions have been reported in squamous cell carcinomas of the head and neck region.

Histologic grade

The histologic grade reflects the degree of differentiation of the tumor cells. The most commonly used grading system for SCC is a modification of the original Broders' system, consisting of three grades based on the amount of keratin, the degree of nuclear atypia, and the mitotic activity. Well-differentiated (grade 1) tumors exhibit abundant intercellular bridges, cytoplasmic keratinization, and keratin pearls. The cells are relatively uniform with minimal nuclear pleomorphism. The mitotic rate is generally low. Moderately differentiated (grade 2) tumors show primarily individual cell keratinization, moderate nuclear pleomorphism, and more numerous mitotic figures than seen in grade 1 tumors. Poorly differentiated (grade 3) tumors show little evidence of squamous differentiation. The tumor cells are immature, with marked nuclear pleomorphism, scant cytoplasm, and numerous mitotic figures per high power field. Necrosis is also common.^{113, 124} Histologic grade may have an effect on response to therapy and prognosis (see section on Prognostic Factors later in this chapter). Currently, the grade of SCC is broadly used in daily practice and included in pathology reports.

Endocervical glandular dysplasia

Endocervical adenocarcinoma in situ (AIS) is recognized as the precursor to HPV-related invasive endocervical adenocarcinoma. However, diagnosis of atypical lesions less severe than AIS is somewhat controversial and not standardized. Support for diagnosis of dysplastic lesions less than AIS stems from demonstration of dysplasia adjacent to AIS and invasive adenocarcinoma,^{125, 126, 127} the younger age of patients with dysplasia vs. AIS and invasive adenocarcinoma,^{127, 128} the presence of high-risk HPV in at least a subset of dysplastic lesions,^{125, 126, 129} and the presence of diffuse p16 expression in the majority of glandular dysplasias in some studies (Fig. 9).¹³⁰ Other studies, however, have found differing results, include absence of coexisting AIS and dysplasia,^{131, 132} absence of HPV in many atypical glandular lesions,^{132, 133, 134} the existence of HPV-negative atypias with high Ki-67 proliferation indices,¹³² and absence of diffuse p16 positivity in glandular dysplasias.^{135, 136}

 

Fig. 9. Endocervical glandular dysplasia. (A) H&E-stained slide shows focal area of atypical glandular epithelium with partial stratification, moderate nuclear atypia, and one mitosis. (B),(C) Immunostains reveal an increased Ki-67 proliferation index (B) but only focal immunoreactivity for p16 (C). (Yellow bars: original magnification)

 

In 2003, Silverberg and colleagues¹³⁷ proposed a three tier scoring system to differentiate among benign glandular lesions, endocervical glandular dysplasia (EGD), and AIS. This scheme gives scores from 0 to 3 to each lesion for: (1) nuclear atypia, (2) stratification, and (3) sum of mitoses/apoptoses per gland (counted in the two most active glands and then averaged per gland). These three scores are then added to result in the total score (Table 2). The study demonstrated a significant increase in agreement with use of the scoring system (52.2% agreement and kappa 0.565 without scoring system, vs. 77.6% agreement and kappa 0.705 with scoring system). It should be noted, however, that in the original study from Silverberg and colleagues, the best reproducibility was obtained by combining the benign and EGD categories into a single “benign/reactive” category (agreement 94%), allowing the accurate distinction between AIS and lesions less than AIS. The authors proposed that this practice be adopted given the poor understanding of EGD.¹³⁷

 

Table 2. Silverberg scoring system for noninvasive endocervical glandular lesions¹³⁷

 

In the United Kingdom, a similarly tiered grading system is employed, termed “cervical glandular intraepithelial neoplasia (CGIN).” Two grades of CGIN are diagnosed: low-grade CGIN (LCGN), which generally corresponds to EGD, and high-grade CGIN (HCGIN), which generally corresponds to AIS.¹³⁸

Given the lack of widespread consensus regarding the diagnosis of EGD, as well as its as yet questionable biologic significance, many authors recommend against its diagnosis.^{139, 140, 141} This is reflected also in the most recent WHO classification. Whereas the prior WHO classification included both glandular dysplasia and AIS under the classification of cervical glandular tumor precursors,¹⁴² the current WHO classification has eliminated the dysplasia category and includes only AIS as a precursor lesion.¹⁰⁶

Adenocarcinoma in situ

The entity of endocervical adenocarcinoma in situ (AIS) has been widely accepted and recognized as the precursor of invasive adenocarcinoma. In addition to the usual HPV-related type of AIS, endometrioid,³² clear cell,¹⁴³ and intestinal (see below) types have also been described. HSIL coexists with 35–71% of adenocarcinomas in situ.^{144, 145, 146}

The majority of AIS lesions are detected initially in the cervical smears of asymptomatic women or incidentally in hysterectomy specimens removed for benign conditions. Some are found in cervical biopsy specimens, endocervical curettage specimens, or cone specimens removed for squamous neoplasia. Colposcopic findings are nonspecific, such as patchy acetowhite lesions in the cervical canal, fused and papillary columnar villi, and abnormal vessels.

Most AIS lesions begin in the region of the squamocolumnar junction and spread proximally. With few exceptions, both the endocervical mucosal surface and the underlying glands are involved. The affected surface may be flat, papillary, or villous in appearance. Whereas normal endocervical cells are arranged in a single layer and have basally located small nuclei with absent to rare nucleoli and mitotic figures, neoplastic endocervical cells demonstrate nuclear enlargement, hyperchromasia, and pseudostratification, with a typically cigar-shaped elongated appearance (Fig. 10). Nucleoli are multiple, and mitotic figures are easily identified within the apical mucin (imparting a “floating” appearance). Apoptotic figures are also frequent. The cytoplasm appears basophilic, clear, or vacuolated. In the deeper portion of the endocervical glands, a sharp transition between the normal and neoplastic cells is often apparent. The normal architecture and branching pattern of the glands is maintained, although some budding and intraglandular proliferation and cribriforming can be seen. The characteristic features distinguishing this lesion from invasive adenocarcinoma are the preservation of normal architecture, the smooth configuration of the glandular profiles, the absence of neoplastic glands deeper than the uninvolved glands, and normal fibromuscular stroma without desmoplasia.

 

Fig. 10. Endocervical adenocarcinoma in situ. (A) The neoplastic endocervical glands retain the branching and budding pattern of normal endocervical glands. These glands have smooth borders and are surrounded by normal fibromuscular stroma without a desmoplastic reaction. At the base of the tumor, malignant cells replace normal endocervical cells. (B),(C) Higher magnification reveals tall columnar neoplastic cells with nuclear stratification (B), hyperchromasia, elongation, irregularity (C), and increased mitoses (red arrows, B,C). (Hematoxylin-eosin stain, red and yellow bars: original magnification). (D) The neoplastic glands are diffusely immunoreactive for p16.

Although the diagnosis of AIS may be made on the basis of cytology and biopsy specimens, it is difficult to separate in situ carcinoma from well-differentiated invasive adenocarcinoma. As both lesions may occur concurrently, cervical conization is usually performed for a definitive diagnosis. Additionally, a newly proposed classification system for endocervical adenocarcinoma may make this distinction less crucial (see below).

Other important differential diagnoses to consider include tubal/tuboendometrioid metaplasia and reactive change. Like AIS, tuboendometrioid metaplasia demonstrates some nuclear enlargement and stratification. Mitotic activity and apoptotic bodies should, however, be rare, and the presence of cilia favors a diagnosis of tubal/tuboendometrioid metaplasia (although rare ciliated AIS does occur). Reactive endocervical cells are mostly seen in a background of inflammation, and demonstrate some nuclear enlargement, pleomorphism, and prominent nucleoli. In contrast to AIS, however, the nuclear chromatin demonstrates a more open appearance, and the nuclei sometimes appear smudged. Additionally, significant mitotic activity and pseudostratification are absent. Other entities which occasionally enter the differential diagnosis are microglandular hyperplasia (distinguished by its classic pattern of crowded glands with bland cuboidal lining cells, vacuoles, and neutrophils), Arias-Stella reaction (distinguished by its classic appearance of clear cytoplasm, enlarged nuclei, and prominent hobnailing, and aided by a known history of recent pregnancy), and endometriosis (distinguished by the usual presence of endometrial-type stroma).

Immunohistochemical stains can be of use in distinguishing benign mimics from AIS. Given that the vast majority of AIS is related to high-risk HPV, it is not surprising that diffuse strong p16 positivity is present in the majority of these lesions.^{130, 135, 147} An important caveat to the use of p16 in this differential diagnosis is that glands with tuboendometrioid metaplasia can also demonstrate p16 expression; however, careful assessment usually reveals a patchy (albeit sometimes extensive) staining pattern, compared with the diffuse pattern seen in AIS.^{130, 135, 147} The Ki-67 proliferation index is also elevated (usually >30%) compared to benign mimics (usually <10%).^{130, 147, 148} Additionally, estrogen and progesterone receptors are negative in AIS, whereas endometriosis and tubal/tuboendometrioid metaplasia are usually positive for ER and PR.^{136, 149}

Estimates based on conization and hysterectomy specimens have found AIS extending as deep as 3–5 mm from the mucosal surface. The linear extent along the cervical canal varies from 0.5 to 25 mm with a mean of 12 mm.¹⁵⁰ If measured from the external os, these lesions may reach up to 30 mm.¹⁵¹ This underscores the need for deep conization to encompass the entire lesion. Young women preferring to retain the uterus may be treated by conization alone and followed regularly by endocervical curettage.¹⁵⁰ However, even if the surgical margins of the conization specimen appear uninvolved, residual tumor may exist. A possible explanation for this is multifocal disease, which is estimated to occur in 15% of cases.¹⁵⁰

In additional to the usual type of AIS, an intestinal type is also occasionally encountered. This type is characterized by goblet cells, sometimes accompanied by Paneth cells and neuroendocrine cells.¹⁵² It is usually admixed with usual type AIS.¹⁵² Based on the rarity of intestinal metaplasia in benign endocervical glands, some authors recommend diagnosing any intestinal metaplasia in the cervix as AIS, even without significant cytologic atypia.¹⁵³ The presence of intestinal metaplasia can also raise concern for a metastatic carcinoma from the gastrointestinal tract. However, the distinction from a lower gastrointestinal tract primary is aided by the typical CK7(+), CK20(-), and p16-diffuse immunoprofile which intestinal AIS appears to maintain.¹⁵⁴ Of interest, however, CDX2, a marker of intestinal differentiation, has been demonstrated to be positive in these lesions.¹⁵⁴

Adenosquamous intraepithelial lesions

The entity of adenosquamous carcinoma in situ described by Steiner and Friedell¹⁵⁵ closely resembles squamous cell carcinoma in situ. Intermixed with the dysplastic squamous cells, however, are cells with vacuolated or basophilic cytoplasm. Mucicarmine and periodic acid-Schiff (PAS) stains reveal mucin production in these cells. Similar change sometimes occurs in the vicinity of adenosquamous carcinomas.

More recently, the entity of “stratified mucin-producing intraepithelial lesion (SMILE)” of the cervix has been described. Park et al.¹⁵⁶ described 18 lesions demonstrating stratified atypical epithelium (similar to HSIL) and containing cytoplasmic mucin (similar to AIS), with distinctive cytoplasmic clearing or vacuolization (Fig. 11). While this lesion is likely akin to the previously described “adenosquamous carcinoma in situ,” the authors proposed an origin from reserve cells, an assertion supported by the location of these lesions near the transformation zone, the occasional undermining of normal columnar epithelium (like reserve cells), and the frequent co-existence of HSIL and AIS.¹⁵⁶ Immunohistochemically, these lesions display a lack of definitive squamous differentiation; when encountered in isolation, they are likely best regarded as a stratified form of AIS or as a high-grade reserve cell dysplasia.^{153, 156} As with typical HSIL or AIS, SMILE demonstrates diffuse p16 positivity.¹⁵⁷

 

Fig. 11. Stratified mucin-producing intraepithelial lesion (SMILE)/adenosquamous carcinoma in situ. Nests of noninvasive, stratified, high-grade neoplasia with a mucin-producing component (pink intracytoplasmic mucin detected by counterstain of Mucicarmin). (Hematoxylin-eosin stain, red bar: original magnification.)  

Cervical carcinomas with glandular differentiation are of heterogeneous cell types, diverse growth patterns, and variable differentiation. The majority of glandular neoplasms are pure adenocarcinomas. The current WHO classification of glandular tumors of the uterine cervix¹⁰⁶ is listed below. Adenosquamous carcinomas will be discussed separately.

 

·         Endocervical adenocarcinoma, usual type

·         Mucinous carcinoma, NOS

o   Gastric type

o   Intestinal type

o   Signet-ring cell type

·         Villoglandular carcinoma

·         Endometrioid carcinoma

·         Clear cell carcinoma

·         Serous carcinoma

·         Mesonephric carcinoma

·         Adenocarcinoma admixed with neuroendocrine carcinoma

 

As previously stated, while the overall incidence of cervical carcinoma as well as the incidence of squamous cell carcinoma has decreased in recent decades in developed countries, the incidence of adenocarcinoma has been rising.⁴ The reasons for this are not yet understood.

The clinical presentation and gross appearance of cervical adenocarcinoma are basically similar to those of SCC. In a series of 55 women with IB adenocarcinoma by Greer and colleagues,¹⁵⁸ 44% of women had no symptoms and 58% (32 of 55) had no gross lesions. The diagnosis was suspected on the basis of abnormal cervical smears in 16 women (29%). Of these, 15 required conization for diagnosis.¹⁵⁸

Early invasive adenocarcinoma

As with early invasive squamous lesions, the definitions of “microinvasion” for cervical adenocarcinoma vary. Several investigators have attempted to define the morphologic criteria for microinvasive adenocarcinoma. Teshima and associates¹⁵⁹ defined early adenocarcinoma as less than 5 mm of stromal invasion as measured from the mucosal surface. All 30 patients in their study were treated by hysterectomy and one woman developed tumor recurrence. Among women with stage I and II cervical adenocarcinoma up to 5 mm in depth, Berek and colleagues¹⁶⁰ found that two of 24 women (8%) had pelvic lymph node metastasis and the overall 5-year survival rate was 92%. Thus, adenocarcinomas as superficial as 5 mm have a small risk of pelvic nodal metastasis. In the United States, a FIGO stage IA1 tumor (≤3 mm in depth) is usually considered microinvasive, while some institutions in the United Kingdom include also FIGO stage IA2 (≤5 mm in depth) in the definition.¹⁵³ Therefore, as with SCC, avoidance of the term “microinvasion” is preferable. Unlike with SISCC, however, no recent standardized guidelines have been established, and so reporting instead the FIGO stage without use of the term “microinvasion” is recommended by some authors.¹⁵³ Depth of invasion should be measured from the basement membrane of the overlying abnormal epithelium to the point of deepest invasive tumor (Fig. 12).

 

Fig. 12. Early invasive endocervical adenocarcinoma. This small focus of adenocarcinoma forms multiple irregular tongue-like protrusions from the periphery of endocervical glands. These protrusions are associated with fibrotic stroma and chronic inflammation. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

The distinction of early invasive adenocarcinoma and AIS can be challenging. In cases with clearly infiltrative glands, stromal desmoplasia, and/or destructive invasion, the diagnosis can be rendered without significant difficulty. However, frequently these features are absent, and the pathologist must rely on more subtle findings such as a haphazard low-power appearance of the glands, glandular confluence and complexity, excessively deep glands (beyond the deepest benign gland), and proximity to thick-walled vessels.¹⁶¹ A recently proposed pattern-based classification scheme for usual type endocervical adenocarcinoma may reduce the burden of making this distinction in difficult cases (see below).

Invasive endocervical adenocarcinoma, usual type

 

Endocervical adenocarcinoma of the usual type is the most common type of endocervical adenocarcinoma. Well-differentiated tumors demonstrate mostly glandular architecture, with cribriforming, confluence, and sometimes formation of papillae. The lining cells are columnar and often stratified, and have eosinophilic or finely vacuolated pale staining cytoplasm resembling normal endocervical cells. Mitotic activity and apoptotic bodies are abundant. Moderately differentiated tumors demonstrate a greater proportion of solid growth (11–50%), whereas poorly differentiated tumors demonstrate >50% solid growth (Fig. 13). Poorly differentiated tumors can also have anaplastic cells and cells with a signet ring cell appearance.

 

Fig. 13. Invasive endocervical adenocarcinoma, usual type. Moderately differentiated invasive adenocarcinoma consisting of small irregular glands and solid nests (A). Higher power view (B) shows vacuolated cytoplasm with mucinous features. Nuclear atypia is apparent. (Hematoxylin-eosin stain, red bars: original magnification.)

 

 

 

The traditional treatment for invasive endocervical adenocarcinoma was radical hysterectomy with pelvic lymph node dissection. However, the ability to avoid hysterectomy and therefore preserve fertility in women of child-bearing age, as well as to avoid the morbidity of lymphadenectomy, is clearly desirable. It has been demonstrated that FIGO stage IA1 carcinomas (≤3 mm depth, ≤ 7 mm horizontal extent) are amenable to more conservative treatment (e.g. cold knife cone or simple hysterectomy without lymph node dissection) with a very low risk of extracervical spread and recurrence.¹⁶² However, patients with stage IA1 carcinomas can still have lymph node metastases and die of disease.^{162, 163} Additionally, while more radical surgery is usually recommended for patients with stage IA2 carcinoma, the risk of lymph node metastasis and death has been demonstrated to be low in these patients as well.¹⁶³ Compounding this issue is the difficulty and subjectivity involved in measuring depth, particularly in a well-differentiated carcinoma with associated AIS, in which the invasive and in situ component cannot always be reliably distinguished.

Given these issues, a new system of classification for usual type endocervical adenocarcinoma has recently been proposed based on a multi-institutional study.¹⁶⁴ Termed the “Silva system,” this scheme relies on pattern, rather than tumor depth, to stratify patients into risk categories. Three patterns are defined (Table 3).

 

Table 3: The Silva system for pattern-based classification of endocervical adenocarcinoma of usual type¹⁶⁴

 

In the initial study looking at data from 352 patients, the authors found that none of the patients with Pattern A adenocarcinomas had lymph node metastases, compared to 4.4% for Pattern B and 23.8% for Pattern C.¹⁶⁴ Interestingly, although the average depth of invasion increased from Pattern A to C, there was significant overlap among the patterns, with 27.4% of Pattern A tumors having a depth of invasion >5 mm, and 10.6% of the Pattern C tumors having a depth of invasion ≤3 mm. Additionally, the average horizontal spread for Pattern A tumors was 8.6 mm (range 1.5–20 mm), compared to 16.3 mm (range 1.2–30 mm) for Pattern C. Therefore, a large number of the Pattern A tumors (81%) were beyond a FIGO stage IA1, and thus beyond the usual cut-off for conservative vs. radical treatment. Based on these data, it appears that the newly proposed pattern-based classification system may be superior to depth of invasion in predicting the risk for lymph node metastasis and identifying patients with tumors amenable to conservative treatment.¹⁶⁴ Although reproducibility studies are as yet limited, one study using blinded review of 48 cases found that a consensus diagnosis with the new system was achieved in 50% of cases (kappa values between 0.24 and 0.84). Agreement was improved using two tiers (A vs. B/C), with a consensus diagnosis reached in 81.3% of cases (kappa values between 0.33 and 0.92).¹⁶⁵ While additional studies are needed to validate this system, it appears very promising as a superior way to diagnose and treat patients with endocervical adenocarcinoma.

Mucinous carcinoma

Mucinous carcinomas of the cervix are generally classified according to the subtypes discussed in this section. However, mucinous carcinomas which do not demonstrate features of any of these specific subtypes are classified as “mucinous carcinoma, NOS.”¹⁰⁶

Mucinous carcinoma, gastric type

This category includes the tumor known as “minimal deviation adenocarcinoma” or “adenoma malignum.” This is an extremely well-differentiated adenocarcinoma closely resembling normal endocervical glands,^{166, 167} which comprises approximately 1% of cervical adenocarcinomas.¹⁶⁸ This variant deserves special recognition because of the inherent difficulty in its diagnosis, as well as its aggressive behavior, belied by its deceptively bland appearance. The tumor mostly retains the branching pattern of normal endocervical glands, has minimal nuclear atypia, and causes minimal stromal response (Fig. 14). Clues for the diagnosis of minimal deviation adenocarcinoma include angulated, cystic glands with a vaguely haphazard architecture at low power and the presence of glands deep in the cervical stroma. Encroachment of the blood vessels and nerve fibers adds further support for stromal invasion. Careful survey of individual lining cells reveals at least focal nuclear atypia with enlargement, hyperchromasia, and uneven chromatin. Nucleoli may be evident.

 

Fig. 14. Cervical adenocarcinoma, minimal deviation type (adenoma malignum). Haphazardly arranged, branching, budding glands infiltrate into deep cervical stroma (A). Neoplastic cells closely mimic normal endocervical cells, with tall columnar configuration, abundant mucinous cytoplasm, and small basally located nuclei (B). Focal nuclear irregularity and small nucleoli are however evident. (Hematoxylin-eosin stain, red bars: original magnification.)

 

 

Although similar characteristics have also been observed in well-differentiated endometrioid, clear cell, and mesonephric carcinomas,¹⁶⁸ most authors apply the terms adenoma malignum and minimal deviation adenocarcinoma only to the mucinous type.

Minimal deviation mucinous adenocarcinomas of the cervix are associated with Peutz-Jeghers syndrome, and 55% of sporadic cases in one study were demonstrated to have mutations in the Peutz-Jeghers syndrome-associated tumor suppressor gene STK11.¹⁶⁹

Support for a gastric phenotype comes from studies demonstrating histochemical positivity for gastric mucin and immunohistochemical positivity for the gastric markers HIK1083 and MUC6.^{170, 171, 172} Additional immunohistochemical characteristics include negativity for ER and PR, at least focal positivity for CEA, positivity for CK7, and variable positivity for CK20, PAX8, and Her2/neu.^{170, 173, 174} Diffuse positivity for p53 has also been described in some tumors.¹⁷⁴ Additionally, these tumors are not associated with high-risk HPV, and p16 is usually non-diffuse.^{173, 174}

Tumors that have a gastric phenotype but which demonstrate non-well-differentiated areas may be classified as gastric-type adenocarcinoma.¹⁰⁶

Gastric-type mucinous adenocarcinomas of the cervix, including the deceptively bland minimal deviation adenocarcinoma, are reported to be associated with aggressive behavior and a worse prognosis compared to usual type endocervical adenocarcinoma, with gastric-type adenocarcinomas having a higher risk for extracervical spread, a higher risk of recurrence, and a decreased 5-year disease-free survival (25% vs. 75%).^{173, 175} Delay in correct diagnosis due to difficulty in screening for these tumors may account for some of the advanced cases.

Equally important, benign conditions such as tunnel clusters, hyperplastic mesonephric ducts, deep Nabothian cysts, and endometriosis, should not be confused with minimal deviation adenocarcinoma. Careful assessment for the features discussed above as well as use of immunohistochemistry can aid in this differential diagnosis.

It has been proposed that the hyperplastic endocervical lesion termed “lobular endocervical glandular hyperplasia” (LEGH) may be a precursor to gastric-type adenocarcinomas, based on co-existence of the two entities, evidence of a gastric phenotype in LEGH, and shared chromosomal imbalances between LEGH and gastric-type adenocarcinomas.^{176, 177}

Mucinous carcinoma, intestinal type

Intestinal type mucinous carcinomas of the cervix are defined in the current WHO classification as mucinous adenocarcinomas with areas of intestinal type differentiation.¹⁰⁶

These tumors are composed of cells similar to those seen in colorectal adenocarcinomas, characterized by the presence of goblet cells. Glandular and papillary growth patterns can be seen (Fig. 15). Neuroendocrine cells and occasionally Paneth cells may be present. Intestinal differentiation may be found diffusely or only focally within a mucinous carcinoma. The main differential diagnosis is with metastatic colonic adenocarcinoma. Primary cervical intestinal type adenocarcinoma is generally immunoreactive with CK7 and negative or only focally positive for CK20.¹⁵⁴ As with intestinal type AIS, positivity for CDX2, indicating intestinal differentiation, is also frequently present.¹⁵⁴ The presence of high-risk HPV has been identified in many of these tumors,¹⁷⁸ and diffuse positivity for p16 is often seen.¹⁵⁴

 

Fig. 15. Cervical adenocarcinoma of intestinal type. Intermediate power shows infiltrating adenocarcinoma with a glandular growth pattern. Tumor cells contain abundant intracytoplasmic mucin. Goblet cells can be appreciated. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

Mucinous carcinoma, signet-ring cell type

These rare carcinomas are defined as having focal or diffuse signet-ring cell differentiation.¹⁰⁶ Signet-ring cell features may be seen in either usual-type endocervical adenocarcinomas which are associated with HPV, or with the HPV-independent gastric-type adenocarcinomas.¹⁰⁶

 

Villoglandular carcinoma

Young and Scully¹⁷⁹ reported a series of 13 villoglandular papillary adenocarcinomas of the uterine cervix. This tumor occurred mostly in young women (mean age, 33 years). The lesions were described clinically as polypoid, condylomatous, eroded, nodular, white, friable, or fungating. Microscopically, the superficial portion of the tumor consisted of complex papillae lined by well-differentiated endocervical cells (Fig. 16). In the deeper portion of the tumor, neoplastic cells formed branching tubular glands pushing into fibrous stroma. In six women, the tumor was confined to the superficial one third of cervical wall, whereas deep invasion occurred in two women. After hysterectomy, no tumor recurrence was noted in ten women observed for 2–14 years.¹⁷⁹

 

Fig. 16. Cervical adenocarcinoma, villoglandular type. On the surface are multiple papillary projections consisting of columnar cells with either thick (A) or thin (B) fibrovascular cores. The base of the tumor usually has smooth borders without an infiltrative pattern. (Hematoxylin-eosin stain, yellow and red bars: original magnification.)

 

 

In a subsequent study of 24 cases by Jones and associates,¹⁸⁰ the mean age was 37 years (range 27–54 years), and 50% of women were in their third decade of life. There was history of oral contraceptive use in 63% of women, in contrast to 28% among women having other types of cervical adenocarcinoma (p = 0.02). Grossly, the tumor had an exophytic polypoid appearance. Microscopically, the predominant cell type was endocervical in 50%, endometrioid in 33%, and intestinal in 17%. In all, 33% had coexisting squamous intraepithelial lesions. Five tumors (21%) were entirely in situ without stromal invasion; 75% (18 tumors) were superficially invasive, confined to the inner third of the cervical wall; and 4% (one tumor) invaded 75% of the cervical wall.¹⁸⁰

Treatment modalities included local excision or cone biopsy in five women, simple hysterectomy in four women, and radical hysterectomy in 15 women.¹⁸⁰ All tumors were confined to the cervix without pelvic lymph node metastasis. All women were alive and well 7–77 months (mean 36 months) later.¹⁸⁰ Lymph node metastases, though reported, are rare.¹⁸¹ In view of their distinct clinical and pathologic features, these tumors are separated from other cervical adenocarcinomas. A conservative treatment approach is considered acceptable in many cases, especially in young women who want to retain fertility.¹⁸⁰

It should be emphasized that the term villoglandular adenocarcinoma should be reserved only for those tumors which meet the stringent morphologic criteria. The degree of nuclear atypia should be no worse than moderate. The tumor borders should be smooth, and tumors made up of clear cells and serous cells are excluded. In cervical biopsy specimens and endocervical curettage specimens, there are often fragments of tumor that a have villous pattern. However, in the subsequently excised specimens, some of these tumors prove to have poorly differentiated elements or infiltrative borders. Thus, the diagnosis of well-differentiated villoglandular carcinoma should be made on completely excised specimens only. It has been recommended that tumors which do not meet these criteria or which have lymph-vascular space invasion or more than superficial invasion be treated more aggressively.¹⁸¹

Endometrioid carcinoma

This group of tumors has the appearance of FIGO grade 1 or grade 2 adenocarcinoma of the endometrium. The predominant growth pattern is glandular or less commonly papillary. The lining cells are tall, columnar, and have densely basophilic or eosinophilic cytoplasm (Fig. 17). Endometrioid carcinomas from the endometrium and cervix share a similar histology and immunoprofile, and therefore the diagnosis of cervical origin is justified only if the endometrium is normal after careful sampling for histologic examination. Sometimes, mature metaplastic squamous cells occur within the neoplastic glands.^{5, 182}

 

Fig. 17. Endometrioid carcinoma of the cervix. This tumor has morphology similar to its uterine counterpart, with glandular and cribriform architecture, smooth luminal borders, and foci of squamous differentiation (A). High power demonstrates columnar cells with pseudostratified nuclei and mild to moderate atypia. (Hematoxylin-eosin stain, red bars: original magnification.)

 

Endometrioid carcinomas comprise 5% of endocervical adenocarcinomas.¹⁰⁶ Some authors believe that these tumors have been overdiagnosed in the past due to the endometrioid appearance of some usual type endocervical adenocarcinomas.^{106, 138} Endometrioid carcinomas which represent endometrioid variants of usual type endocervical adenocarcinoma are related to HPV and will demonstrate diffuse p16 positivity. True endometrioid carcinomas, which can arise from cervical endometriosis, are HPV-independent.¹⁰⁶

Clear cell carcinoma

Cervical clear cell adenocarcinoma affects women with or without exposure to diethylstilbestrol (DES) in utero. The age distribution has a bimodal peak, one around 20 years of age (mostly DES-exposed women) and the other in the fifth and sixth decades of life (mostly sporadic cases).¹⁸³ In current practice, DES-associated clear cell carcinomas are rare.

The most common patient complaint is vaginal bleeding, and, on examination, a polypoid, exophytic, or fungating tumor is visible.^{184, 185} In the DES-exposed progeny, the cervical clear cell carcinomas are located mainly in the ectocervix and rarely in the endocervix.¹⁸⁶

Under the microscope, the tumor cells have distinct clear, empty appearing cytoplasm and enlarged, hyperchromatic nuclei, which project into the apical cytoplasm, the so called hobnail appearance. The clear cytoplasm is attributed to the accumulation of abundant glycogen similar in appearance to that seen in secretory endometrial cells. Cells with eosinophilic cytoplasm can also be seen. The cells grow predominantly in tubulocystic, papillary, or solid patterns (Fig. 18). Significant nuclear atypia is appreciable at least focally. Intracytoplasmic hyaline globules and stromal hyalinization are common.

 

Fig. 18. Clear cell carcinoma of the cervix. This exophytic tumor is characterized by papillary and glandular growth patterns with hyalinized stroma. The papillae and glands are lined by intermediate to large tumor cells with clear or eosinophilic cytoplasm and high-grade nuclei. Scattered hobnail cells can be appreciated. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

There is evidence that a subset of these tumors is related to HPV.¹⁸⁷ Survival appears to be similar to other types of cervical carcinoma.¹⁸⁸

Serous carcinoma

A few cervical adenocarcinomas indistinguishable from serous carcinoma of the endometrium or adnexa have been reported.^{189, 190, 191} The tumor microscopically has a complex pattern of papillae with cellular budding and glands with slit-like spaces. Moderate to severe nuclear pleomorphism is usually seen (Fig. 19). Occasionally, psammoma bodies can be identified. An in situ component may be present. Nearly half of reported cases exhibited a second admixed pattern, most commonly low-grade villoglandular adenocarcinoma. Diagnosis of serous adenocarcinoma of the cervix can be made only when metastasis from the endometrium or adnexa is excluded.

 

Fig. 19. Cervical adenocarcinoma of serous type. Cervical serous carcinomas demonstrate the same high-grade cytologic features as their uterine counterparts, with marked nuclear atypia and pleomorphism as well as brisk mitotic activity. (Hematoxylin-eosin stain, red bar: original magnification)

 

 

 

When diagnosed at an advanced stage, these tumors behave aggressively, and poor prognostic factors include younger age, larger tumor size (>2 cm), deep invasion (>1 cm), lymph node metastasis, and elevated CA125. However, stage I tumors have a similar prognosis to other stage I cervical adenocarcinomas.¹⁹¹

Mesonephric carcinoma

The rare entity of mesonephric carcinoma arises from mesonephric remnants in the deep lateral cervical wall. Many of the mesonephric duct carcinomas reported earlier belong to the clear cell adenocarcinoma category by current classification. The tumors may be bulky or exophytic, and can invade deeply.¹⁰⁶

Histologically, the tumors typically consist of tubules, glands, and microcysts containing eosinophilic hyaline material in the lumen (Fig. 20). This eosinophilic material is PAS-positive and mucicarmine-negative by histochemistry.  The tubules are lined by cuboidal cells with variable cytologic atypia and mitotic activity. Other architectural patterns are also described, including ductal, retiform, solid, and sex cord-like structures. Rare cases with spindle cells resembling endometrial stromal sarcoma with osteoid and chondroid metaplasia have been described.¹⁹²

 

Fig. 20. Cervical adenocarcinoma of mesonephric type. Tumor consists of packed tubules and microcysts with infiltrating borders (A). A higher power view shows hyperchromatic and crowded nuclei with frequent mitoses (B). Intraluminal eosinophilic hyaline material is evident. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

Immunohistochemistry is often necessary to confirm the diagnosis, given both the rarity of the tumor and its variable architectural patterns, which can mimic diverse tumor types. It has been demonstrated that mesonephric carcinomas are immunopositive for CD10, epithelial membrane antigen (EMA), vimentin, calretinin, PAX8, HMGA2, and CA125, with variable positivity for ER, CEA, inhibin, TTF1, and HNF1-beta.¹⁹³ Interestingly, although these tumors are unrelated to high-risk HPV, diffuse p16 has been demonstrated in some cases.¹⁹³

The prognosis of mesonephric carcinoma compared to other cervical adenocarcinomas has not been clearly elucidated; however, some cases with aggressive behavior, late recurrences, and distant metastases have been reported.¹⁹⁴

It should be noted that benign hyperplasia of mesonephric ducts can be found deep in the cervical stroma, mimicking adenoma malignum and mesonephric adenocarcinoma.¹⁹⁵ The presence of haphazard infiltrative growth, gland confluence, mitoses, and nuclear atypia assists in making the distinction between mesonephric hyperplasia and carcinoma.¹⁰⁶

Adenocarcinoma admixed with neuroendocrine carcinoma

Mixed carcinomas consisting of adenocarcinoma and small cell or large cell neuroendocrine carcinoma have been described.^{196, 197, 198} Some evidence exists as to the monoclonality of the two components.¹⁹⁶ The behavior is driven by the high-grade neuroendocrine component. Neuroendocrine carcinomas are discussed in more detail in a subsequent section.

Endometrial vs. endocervical carcinoma

Distinguishing endocervical from endometrial carcinomas can sometimes be difficult on biopsies or even in hysterectomies in which the tumor involves both sites. To compound the issue, endometrioid carcinomas of the endometrium can display focal to extensive mucinous differentiation, while endometrioid variants of endocervical adenocarcinoma exist (see above). Ancillary studies can be helpful in difficult cases. Low-grade endometrioid carcinomas of the endometrium are typically positive for ER, positive for vimentin, and negative for CEA; expression of p16 can be seen and is sometimes extensive, but usually with a patchy or mosaic pattern. Usual type endocervical adenocarcinomas, in contrast, are usually negative for ER, negative for vimentin, positive for CEA, and diffusely positive for p16. If the carcinoma in question demonstrates high-grade cytologic features (as with serous or undifferentiated types), the utility of p16 is limited, as high-grade tumors can express diffuse p16 via a non-HPV-related pathway. Useful ancillary studies in this case include p53 (often mutated in high-grade carcinomas) and high-risk HPV in situ hybridization. Additionally, immunohistochemical loss of one or more mismatch repair proteins, indicative of microsatellite instability, would favor an endometrial carcinoma.^{138, 153} It should be noted as well that some overlap in immunohistochemistry exists, especially for mucinous endometrioid carcinomas and endometrioid cervical carcinomas,¹⁹⁹ and so the overall immunoprofile and morphologic setting must be considered. The presence of background preneoplastic lesions (atypical endometrial hyperplasia, endocervical AIS) should also be sought and considered.

Another diagnostic dilemma concerns the microglandular hyperplasia (MGH)-like variant of endometrioid carcinoma. This variant of endometrioid carcinoma demonstrates small closely packed glands, mucin production, and abundant luminal and stromal neutrophils, closely simulating MGH.²⁰⁰ Unlike typical MGH, however, these endometrioid carcinomas generally display more atypia and mitotic activity, and are more likely to present in postmenopausal patients.²⁰⁰ The presence of more typical endometrioid morphology in other areas of the tumor, as well as myometrial invasion, also assists in the distinction from a benign process, although these features may not be seen on the initial biopsy or curettage specimen. It should be noted also that MGH can be exuberant, and atypical forms have been described. Atypical MGH can display various unusual patterns, including solid, pseudoinfiltrative, myxoid, signet ring cell, and hobnail cell features.²⁰¹ Although these lesions are benign, they can have more cytologic atypia (mild to moderate) than typical MGH, and can simulate both MGH-like endometrioid carcinomas as well as endocervical carcinomas. Helpful features in recognizing this entity include the presence of other more typical areas of MGH, continuity with normal cervical tissue, reserve cell hyperplasia, and intracellular vacuoles. In difficult cases, immunohistochemistry can be of use; atypical MGH demonstrates negative or patchy p16, positive ER and PR, and positive p63 in the accompanying reserve cells.

 

Although squamous cell carcinoma and adenocarcinoma are the most common epithelial neoplasms to occur in the cervix, other less common tumors can also occur in this site. The following additional tumor types are included in the current WHO classification:¹⁰⁶

 

• Adenosquamous carcinoma
  • Glassy cell carcinoma
• Adenoid basal carcinoma
• Adenoid cystic carcinoma
• Undifferentiated carcinoma
• Neuroendocrine tumors
  • Low-grade neuroendocrine tumor
    • Carcinoid tumor
    • Atypical carcinoid tumor
  • High-grade neuroendocrine carcinoma
    • Small cell neuroendocrine carcinoma
    • Large cell neuroendocrine carcinoma

 

Adenosquamous carcinoma

Adenosquamous carcinomas are defined by having both a squamous cell carcinoma and an adenocarcinoma component. In 1956, Glucksmann and Cherry²⁰² subdivided adenosquamous carcinomas into mature (35%), signet-ring cell (44%), and glassy cell (21%) types. The current WHO classification includes only “adenosquamous carcinoma” and the poorly differentiated variant “glassy cell carcinoma.”

The squamous component must be malignant (benign squamous metaplasia does not qualify an adenocarcinoma as adenosquamous carcinoma) and usually demonstrates well-differentiated areas with keratinization.¹¹³ The adenocarcinomatous component should have recognizable glands (Fig. 21). Excluded from this diagnosis are SCC with occasional mucin-producing cells, as well as carcinomas with solid growth, mucin production, and no identifiable squamous differentiation (best diagnosed as poorly differentiated adenocarcinomas).¹⁰⁶ Additionally, carcinomas with three cellular components (epidermoid, intermediate, and mucin-producing) are best classified as mucoepidermoid carcinomas; these, unlike adenosquamous carcinomas, demonstrate the t(11;19) translocation described in mucoepidermoid carcinoma of the salivary glands.²⁰³

 

Fig. 21. Adenosquamous carcinoma of the cervix. Well-differentiated squamous cell carcinoma with admixed areas of adenocarcinoma. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

 

Cervical adenosquamous carcinomas are associated with HPV types 18 and 16.²⁰⁴ Monoclonality between the squamous and glandular components has been demonstrated,²⁰⁵ and the tumors are thought to arise from pluripotent reserve cells.¹¹³ Co-existing in situ lesions can include HSIL, AIS, and SMILE (see above).

The prognosis of patients with adenosquamous carcinoma in comparison to SCC or adenocarcinoma is unclear, with conflicting results from studies reporting a worse prognosis for adenosquamous carcinoma vs. no difference in prognosis.^{206, 207, 208, 209}

Glassy cell carcinoma

Glassy cell carcinoma is considered to be a poorly differentiated variant of adenosquamous carcinoma. These are rare tumors with rapid growth, which sometimes present with barrel-shaped cervix.¹⁰⁶

Microscopically, large polygonal tumor cells are arranged in sheets and nests and have abundant eosinophilic to granular “ground-glass” cytoplasm, sharp cell borders, uniformly round to oval nuclei, and giant nucleoli (Fig. 22). Mitotic figures are abundant. Many eosinophils and plasma cells are present in the stroma. In the original description of this entity,²⁰² tumor cells had PAS-positive material but no mucinous substance. However, in the study by Maier and Norris,²¹⁰ seven of eight tumors studied by the mucicarmine stain were positive. Three of eight neoplasms contained glandular lumina, and three others had squamous differentiation. One tumor had both glandular and squamous foci. By electron microscopic study, the glassy appearance corresponded to abundant polyribosomes and rough endoplasmic reticulum. The tonofilaments were scant.²¹¹ Although no intracytoplasmic lumina were identified, there were intercellular spaces lined by microvilli to suggest glandular differentiation. Some tumor cells also contained mucinous material in the cytoplasm.²¹¹ These histochemical and ultrastructural findings support the poorly differentiated nature of these neoplasms and the presence of glandular differentiation in some of the tumor cells.²¹¹ Tumor cells are reactive for low and high molecular cytokeratin, MUC1, and MUC2, but are negative for estrogen or progesterone receptors.

 

Fig. 22. Adenosquamous carcinoma of glassy cell type. (A) Tumor consists of sheets of large cells with abundant amphophilic "ground-glass" cytoplasm and well-defined cell borders. Areas of glandular architecture (upper left corner) can be appreciated. (B) Nuclei are large and relatively uniform with vesicular chromatin and prominent nucleoli. A significant inflammatory infiltrate is present. (Hematoxylin-eosin stain, red bars: original magnification.)

 

These tumors have been traditionally regarded as aggressive malignancies with a limited response to surgery and radiation,²¹² but some groups have reported greater treatment success with adjuvant or neoadjuvant chemotherapy.^{213, 214, 215, 216}

Adenoid basal carcinoma

 

This rare cervical tumor resembles basal cell carcinoma of the skin in its histologic appearance. Most patients are postmenopausal and asymptomatic. The cervix is grossly normal and lesions are often detected following abnormal pap smears and incidentally in cervices removed for other reasons. Microscopically, basaloid cells with scanty cytoplasm and uniformly small, round nuclei are arranged in solid nests. These nests are grouped together in a lobular pattern. Cells in the outermost layer have a distinct palisaded nuclear arrangement. Centrally, glandular and squamous metaplasia, as well as cystic spaces containing necrotic debris, may occur (Fig. 23).

 

Fig. 23. Adenoid basal carcinoma of the cervix. This tumor consists of small basaloid nests (left) and large nests in a lobule with squamous metaplasia (right). The basaloid tumor cells are small with scant cytoplasm and a palisaded nuclear arrangement. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

In most reported cases, mitotic activity was absent to low, vascular lymphatic invasion was not seen, and behavior was reported to be essentially benign.^{217, 218} This led to the proposal that the term “adenoid basal epithelioma” be used for this type of tumor.²¹⁸ The bulk of the cases reported in the literature would fall into this category, consisting of a low-grade tumor similar to basal cell carcinoma of the skin, with a generally benign behavior. It was also proposed that the entity termed “adenoid basal hyperplasia,” a similar lesion confined to superficial endocervical glands, represented early adenoid basal epithelioma.²¹⁸ It has been proposed that the term “adenoid basal carcinoma” be reserved for infiltrative neoplasms with stromal desmoplasia and malignant cytologic features.¹¹³ One reported case of an adenoid basal carcinoma with metastasis to the lung demonstrated an appearance similar to morpheaform basal cell carcinoma of the skin.²¹⁷ It should be noted, however, that in the current WHO classification, retention of the term “adenoid basal carcinoma” is recommended.¹⁰⁶

Most adenoid basal carcinomas have coexisting HSIL, and some are associated with other invasive tumors, including invasive squamous cell carcinoma and adenoid cystic carcinoma.^{218, 219}

The differential diagnosis includes adenoid cystic carcinoma, which presents with infiltrative cribriform glands associated with extracellular mucinous material or hyaline cylinders. Cytologic atypia is evident in the tumor cells. Also in the differential diagnosis is basaloid squamous cell carcinoma, in which the tumor cells are cytologically malignant and mitotically active, with a desmoplastic reaction associated with the infiltrative tumor nests.

The presence of high-risk HPV, along with diffuse p16 expression, has been demonstrated in these tumors.^{219, 220, 221} Mutation in TP53 has also been reported.²²⁰

Adenoid cystic carcinoma

 

Adenoid cystic carcinoma of the female lower genital tract occurs most commonly in the Bartholin gland. This is followed by the uterine cervix, affecting primarily postmenopausal women in their seventh decade of life, about 20 years later than squamous cell carcinoma. The histologic features are similar to those occurring in the salivary gland. It is suggested that multipotent reserve cells in the endocervical glands acquire myoepithelial differentiation, which is not normally seen in the cervix.²²²

Histologically, basaloid cells are typically arranged in cribriform glands with hyaline or mucinous material in the microcystic spaces (hyaline cylinders) (Fig. 24). Tubules and solid nests are less common, and tumors with predominantly solid growth patterns are associated with a worse prognosis.²²³ The individual cells have scanty cytoplasm and small, uniform, hyperchromatic nuclei. There is often palisading at the periphery of the cell nests. Mitotic figures are variable depending on the degree of differentiation.²¹⁷ Necrosis is common, as is lymph-vascular space invasion.

 

Fig. 24. Adenoid cystic carcinoma of the cervix. This infiltrating carcinoma displays large nests with solid and cribriform growth patterns. The tumor cells are basaloid with hyaline material in the lumen. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

In about 50% of cases, squamous differentiation is apparent. In such cases, squamous cells replace the glandular lumina partially or completely. When squamous elements predominate, adenoid cystic carcinoma may not be recognized in a small biopsy specimen. Adenoid cystic carcinoma may also be associated with HSIL; because of this, some women are detected initially by abnormal cervical smears. Other types of adenocarcinoma, undifferentiated carcinoma, or sarcoma may sometimes coexist with adenoid cystic carcinoma.^{217, 224}

In one study, 3–5 year survival rates for patients with stage I adenoid cystic carcinoma were 56% compared with 27% for stage II. None of the patients with stage III or IV disease survived.²²⁵Most of the treatment failures were caused by distant and/or local pelvic recurrence. Metastases occurred most frequently in the lung (44%) and less commonly in the bone, liver, and brain. With only 32% of patients free of disease at last follow-up, the overall prognosis of adenoid cystic carcinoma is worse than that of squamous cell carcinoma or pure adenocarcinoma of the cervix.²²⁵ In one review, bulky early stage tumors were found to be best treated with combined surgery and chemoradiation.²²⁶

Immunohistochemically, positivity for epithelial markers (e.g. AE1/AE3, CAM 5.2) and myoepithelial markers (e.g. p63, SMA, calponin) has been described.^{106, 217, 222} Recent studies have shown that CD117 is a useful biomarker for adenoid cystic carcinoma and can be used to differentiate it from adenoid basal carcinoma of the cervix.²²⁷ High-risk HPV has also been identified in these tumors.²²⁸ The MYB-NFIB gene fusion has been found in adenoid cystic carcinomas of various sites (although not specifically the cervix).²²⁹

Neuroendocrine tumors of the cervix

 

In the current WHO classification, neuroendocrine tumors of the cervix are divided into low-grade neuroendocrine tumors (NET) and high-grade neuroendocrine carcinomas. The low-grade tumors consist of carcinoid tumor and atypical carcinoid tumor, while the high-grade tumors include small cell and large cell neuroendocrine carcinomas (Fig. 25).¹⁰⁶ Low-grade NET is very uncommon in the cervix. Typical carcinoid tumor, also known as low-grade NET, grade 1, demonstrates histologic features resembling the typical carcinoid seen in other parts of the body. Architectural patterns include organoid growth, spindling, nests, and trabeculae, and the cells are characterized by abundant cytoplasm and granular (“salt and pepper”) chromatin. Atypical carcinoid tumor, also known as low-grade NET, grade 2, is distinguished from typical carcinoid tumor based on its greater cytological atypia (mild to moderate), increased mitotic activity, and foci of necrosis. Unlike in other sites, the utility of specific Ki-67 proliferative indices or specific mitotic counts as thresholds for grading of NET has not been demonstrated in the cervix.¹⁰⁶

 

Fig. 25. Neuroendocrine tumors of the cervix. (A) Typical carcinoid tumor shows glandular and trabecular growth patterns with minimal cytologic atypia and rare mitosis. (B) Atypical carcinoid tumor has glandular and trabecular growth patterns with moderate cytologic atypia and increased mitoses. (C) Small cell neuroendocrine carcinoma has sheets and trabeculae of small ovoid to spindled tumor cells with scant cytoplasm and hyperchromatic nuclei. Mitoses and apoptoses are numerous. (Hematoxylin-eosin stain, yellow and red bars: original magnification.)

 

Small cell neuroendocrine carcinoma is the most common neuroendocrine tumor of the cervix. Small cell neuroendocrine carcinoma of the cervix is morphologically indistinguishable from small cell neuroendocrine carcinoma of the lung, and a large proportion also express TTF-1.²³⁰ Small cell neuroendocrine carcinoma (also known as neuroendocrine carcinoma, small cell type, grade 3) is characterized by sheets and cords of cells diffusely infiltrating a delicate fibrovascular stroma, simulating lymphoma (Fig. 26). The tumor cells have round to ovoid, small to intermediate sized nuclei. The nuclear chromatin ranges from coarsely granular (“salt and pepper”) to dark and sometimes smudged. Nucleoli are inconspicuous and mitotic figures are frequent. The cytoplasm is scant, resulting in nuclear molding and high nuclear-to-cytoplasmic ratios. Necrosis and crush artifact are common. Large cell carcinomas are characterized by more abundant cytoplasm and larger nuclei with prominent nucleoli. In addition to the diffuse infiltrative pattern, tumor cells are also arranged in trabeculae, ribbons, and rosettes. Occasionally, squamous cell carcinoma and/or adenocarcinoma coexist with neuroendocrine carcinoma.

 

Fig. 26. Small cell neuroendocrine carcinoma. (A) Tumor demonstrates diffuse infiltrative pattern made up of sheets of malignant cells. The presence of crush artifact with smudged nuclei is characteristic. The small nuclei are hyperchromatic and have coarsely granular compact chromatin. The cytoplasm is scant, resulting in nuclear molding. Mitotic activity is high. (B) Tumor is diffusely immunoreactive for CD56. (Hematoxylin-eosin stain, yellow and red bars: original magnification.)

 

Small cell carcinomas are believed to derive from multipotent cells or argyrophilic cells in the basal cell layer of the endocervical mucosa.²³¹ The diagnosis of neuroendocrine tumors in the cervix partly relies on immunoreactivity for neuroendocrine markers, which include synaptophysin, neuron-specific enolase (NSE), chromogranin, and CD56, although some high-grade neuroendocrine carcinomas fail to express these markers.²³⁰ There is a strong association with high-risk HPV, in particular HPV type 18.^{232, 233}

The prognosis of this group of tumors is related to the extent of disease and the degree of differentiation. High-grade neuroendocrine carcinomas are highly aggressive with a propensity for local and distant spread.^{234, 235} One study of 31 neuroendocrine tumors of the cervix (including two atypical carcinoids, four large cell neuroendocrine carcinomas, and 25 small cell neuroendocrine carcinomas) demonstrated that the mean survival time for all patients was 32.3 months. The 2- and 5-year survival rates were 54.8% and 31.5% for all patients, respectively.²³⁶ When treated with radical hysterectomy and pelvic nodal dissection, one study of small cell carcinomas reported four of six (67%) patients to have pelvic nodal metastasis and five of eight (63%) patients to develop tumor recurrence.¹⁴⁴ Sevin and colleagues²³⁷reported 12 women with small cell carcinoma, including one FIGO stage IA, ten stage IB, and one stage II. When compared with stage IB and II cervical squamous carcinoma and adenocarcinoma combined, small cell carcinoma had a higher frequency of lymph-vascular space invasion (82% vs. 62%), more frequent lymph node metastasis (45.5% vs. 18.9%), and a lower 5-year survival rate (36.4% vs. 71.6%). Only 42% (5 of 12) of patients were disease free at the time of report. In view of these findings, a combined therapy of surgery, radiotherapy, and cytotoxic chemotherapy is recommended.²³⁷

Some other rare malignancies of Müllerian origin can develop in the uterine cervix. These include carcinosarcoma (malignant mixed Müllerian tumor) (Fig. 27), leiomyosarcoma (Fig. 28), adenosarcoma (Fig. 29), and endometrial stromal sarcoma (Fig. 30). All these tumors show histology similar to their uterine and adnexal counterparts. Overall, carcinosarcoma and leiomyosarcoma behave more aggressively than adenosarcoma and stromal sarcoma. Recognition of these rare entities is valuable for early detection and appropriate clinical management.

Carcinosarcomas (malignant Müllerian mixed tumors, MMMT) of the uterine cervix are rare neoplasms. It seems that the epithelial differentiation of carcinosarcoma in the cervix is different from its counterpart in the uterus and ovaries. Grayson and colleagues²³⁸ reported eight cases of carcinosarcoma in the cervix. Patients' ages ranged from 32 to 93 years. Seven cases showed in situ squamous cell carcinoma. The invasive epithelial component was composed of combined adenoid basal carcinoma, basaloid SCC, and adenoid cystic carcinoma in two cases. Keratinizing SCC, large cell nonkeratinizing SCC, undifferentiated carcinoma, and basaloid SCC predominated in the remaining tumors, one of which had admixed adenoid cystic carcinoma. The sarcomatous component was homologous and spindled with admixed myxoid areas in three lesions. Polymerase chain reaction detected HPV DNA in all eight cases. In situ hybridization probes to HPV types 6, 11, 16, 18, 31, and 33 demonstrated integrated HPV 16 in three cases.²³⁸

Embryonal rhabdomyosarcoma, in particular the botryoid type (sarcoma botryoides), is an aggressive mesenchymal neoplasm which can occur in the gynecologic tract, most commonly in children. While the vagina is a more common site of occurrence for this tumor, cervical sarcoma botryoides has also been described, most often occurring in an older subset of patients (second decade) and also with a better prognosis than its vaginal counterpart.^{239, 240} Cervical rhabdomyosarcomas have also been reported in adult patients.^{241, 242} Sarcoma botryoides grossly presents as a “grape-like” mass (giving rise to the “botryoid” nomenclature), and histologically consists of a hypocellular and myxoid spindle cell neoplasm with scattered hypercellular tumor cell aggregates as well as a characteristic concentration of tumor cells just beneath the benign overlying epithelium (cambium layer) (Fig. 34). Rhabdomyosarcomas demonstrate skeletal muscle differentiation, and the presence of rhabdomyoblasts, present either as round cells with eosinophils globules and an eccentric nucleus, or as elongated cells with eosinophilic cytoplasm and sometimes characteristic cross-striations (“strap cells”), is a helpful diagnostic feature. Islands of benign cartilage may also been seen 40–45% of cases.^{240, 241} The tumors cells demonstrate immunohistochemical positivity for desmin and myogenin. In recent years, cervical sarcoma botryoides has been identified as one of the neoplasms associated with the DICER1-related inherited cancer syndrome.²⁴³

 

Fig. 27. Malignant mixed Müllerian tumor (carcinosarcoma) of the cervix. The tumor is biphasic. The epithelial component consists of squamous cell carcinoma, adenoid basal carcinoma, and adenoid cystic carcinoma (A–C). The stromal component is mainly undifferentiated sarcoma (C). (Hematoxylin-eosin stain, red bars: original magnification.)

 

 

 

Fig. 28. Leiomyosarcoma of the cervix. This leiomyosarcoma from the cervix is composed of epithelioid tumor cells with atypical and pleomorphic nuclei. The overlying epithelium consists of normal endocervical cells. (Hematoxylin-eosin stain, yellow bar: original magnification.)

 

 

 

 

Fig. 29. Müllerian adenosarcoma of the cervix. The tumor consists of large and branching benign glandular structures surrounded by cellular atypical stromal cells (stromal cuffing). A focus of overlying normal endocervical epithelium can be seen in the upper left corner. (Hematoxylin-eosin stain, red bar: original magnification.)

 

 

 

 

Fig. 30. Low-grade endometrial stromal sarcoma of the cervix. The tumor consists of small and uniform endometrial stromal cells infiltrating into endocervix (A) and ectocervix (B). (Hematoxylin-eosin stain, yellow bars: original magnification.)

 

 

 

 

Other less common malignant neoplasms include aggressive angiomyxoma (Fig. 31), lymphoma (Fig. 32), malignant melanoma, choriocarcinoma (Fig. 33), yolk sac tumor, Wilms' tumor, and others. These are detailed elsewhere.^{5, 244}

 

Fig. 31. Aggressive angiomyxoma involving the cervix. The tumor is composed of mainly bland spindle and oval cells within a myxoid matrix. Thick and thin-walled vessels with hyaline changes are present. The tumor has an infiltrating growth pattern. (Hematoxylin-eosin stain, yellow bar: original magnification.)

 

 

 

 

Fig. 32. Diffuse large B-cell lymphoma of the cervix. This cervical biopsy is completely replaced by malignant lymphocytes with extensive tumor necrosis. Diagnosis was confirmed by immunostains (not shown). (Hematoxylin-eosin stain, yellow bar: original magnification.)

 

 

 

 

Fig. 33. Choriocarcinoma involving the cervix. The tumor consists of a sheet of cytotrophoblastic cells with areas of hemorrhage and scattered syncytiotrophoblastic cells. A normal endocervical gland is seen on the left side. (Hematoxylin-eosin stain, yellow bar: original magnification.)

 

 

 

 

Fig. 34. Botryoid embryonal rhabdomyosarcoma of the cervix. Low-power demonstrates a hypocellular neoplasm with a distinct cambium layer as well as hypercellular foci (A). Higher power of a hypercellular focus demonstrates spindled tumor cells with characteristic rhabdomyoblasts (arrows).

 

 

 

Metastatic secondary tumors

 

Finally, secondary metastatic tumors to the uterine cervix occur most commonly from direct extension of an adjacent malignancy, such as those of the endometrium and vagina.^{5, 244} Less commonly, tumors of the breast (Fig. 35), ovary, colon, and stomach metastasize to the cervix by lymph-vascular spread.^{5, 244}

 

Fig. 35. Metastatic breast carcinoma in the cervix. (A) Metastatic ductal carcinoma in endocervix represented by multiple tumor nests in the stroma and lymph-vascular spaces. (B) Metastatic lobular carcinoma shows infiltrating cords and individual cells in the cervical stroma. (Hematoxylin-eosin stain, yellow and red bars: original magnification.)

 

Various pathologic features have been demonstrated to have prognostic significance in patients with cervical cancer. Some of these have been discussed earlier in this chapter. Selected pertinent literature is discussed below.

Several large series have applied statistical models to identify important prognostic parameters of cervical carcinoma among women treated by radical surgery and radiation therapy (Table 4). Sevin and associates²⁴⁵ evaluated women with stage I or II carcinoma who were treated by radical hysterectomy and pelvic lymphadenectomy. By univariate analysis, the disease free survival rates were closely related to the depth of stromal invasion, tumor size, presence or absence of lymph-vascular space invasion, pelvic lymph node status, tumor volume, and clinical stage.²⁴⁵ Kamura and colleagues²⁴⁶ examined a similar patient population and found that by univariate analysis, 5-year survival rates were correlated to the lymph node status, cell type (squamous cell carcinoma vs. adenocarcinoma), tumor dimension, depth of cervical wall invasion, lymph-vascular space invasion, and parametrial invasion.²⁴⁶ Fuller and colleagues²⁴⁷ studied 431 women with stage IB or IIA carcinoma treated by radical hysterectomy, including 85% squamous carcinomas, 9% adenocarcinomas, and 3% adenosquamous carcinomas. A decreased survival was strongly related to the presence of pelvic lymph node metastasis.²⁴⁷ Among node-negative cases, adenocarcinoma cell type, increasing tumor size, deeper stromal invasion, and high histologic grade were associated with decreased survival.²⁴⁷  Pelvic lymph node metastasis was found in none of 62 tumors involving the inner one third of the cervical wall, 12% of tumors invading up to the middle third, and 24% of tumors extending into the outer third.²⁴⁷

 

Table 4. 5-year survival rates in surgically treated cervical carcinomas

 

 

Examining the question of depth from a different perspective, Kishi and colleagues²⁴⁸ measured the thickness of uninvolved cervical stroma from the deepest tumor to the external cervical wall in 287 stage IB, IIA, and IIB cervical squamous cell carcinomas. The pelvic nodal metastatic and 5-year cancer death rates were 7% and 8%, respectively, when the uninvolved stroma measured greater than 3 mm. Corresponding figures were 37% and 26% when the uninvolved stroma measured less than 3 mm. The authors felt that the uninvolved stroma acted as a barrier to cancer spread, and its width was therefore a more important measurement than the depth of tumor invasion.²⁴⁸

Parametrial spread carries important prognostic information. Its presence or absence should be noted in all pathology reports. Tumor extension to this highly vascular site occurs by contiguous spread, and less often from lymphatic invasion (Fig. 36). When present, parametrial invasion is associated with a higher incidence of vascular invasion, positive lymph nodes, recurrence, and death.^{111, 249}

 

Fig. 36. (A) Tumor extension into the parametrial fibroadipose tissue (left), with adjacent deep cervical stroma containing smooth muscle and blood vessels (right). (B) Venous invasion in the parametrial tissue. The artery in the center of the field is not invaded by tumor. (Hematoxylin-eosin stain, original magnification A: 40X, B: 100X.)

 

 

 

Assessing for the prognostically relevant factor of lymph-vascular space invasion can be challenging. Shrinkage artifact after formalin fixation often results in clear empty spaces at the periphery of tumor nests, simulating a vascular space. These artifactual spaces do not have well-defined endothelial cells (Fig. 37). In true vascular invasion, the tumor cells are partially adherent to the endothelial cells, which should be clearly identifiable. In addition, blood and sometimes fibrin thrombi are present in the vascular lumen. The frequency of lymph-vascular space invasion is closely related to the depth of stromal invasion.²⁵⁰ Vascular invasion is associated with higher rates of pelvic nodal metastasis and tumor recurrence, and with decreased survival in stage I and II squamous cell carcinoma and adenocarcinoma.^{111, 246, 247, 250, 251} This association between vascular invasion and disease recurrence has not been observed in later stages, however. In fact, several studies of stage II and III cervical squamous carcinomas have found that vascular invasion had no bearing on long-term survival.²⁵²

 

Fig. 37. Lymph-vascular space invasion. (A) Shrinkage artifact around the tumor nests simulates lymph-vascular space invasion. (B) True lymph-vascular spaces should demonstrate clearly identifiable endothelial cells. The malignant squamous cells are partially adherent to the vessel wall. (Hematoxylin-eosin stain, original magnification A: 200X, B: 400X.)

 

 

 

The frequency of pelvic lymph node metastasis is influenced by such parameters as FIGO stage, tumor size, depth of invasion, lymph-vascular space invasion, and histologic grade (Table 5).^{111, 247, 253, 254, 255} In some series, 15% of clinical stage I and 26–35% of stage II cervical carcinomas had positive lymph nodes at the time of diagnosis.^{247, 256, 257} The nodal groups most frequently involved are the paracervical, obturator, and external iliac lymph node chains (Fig. 38).²⁵⁸ The prognostic significance of lymph node involvement is dramatic. In one study of women with stage I or II cervical adenocarcinoma treated surgically, lymph node metastases in the pelvic or paraaortic region occurred in 15% of stage I and 40% of stage II tumors. In the presence of pelvic lymph node metastasis, the 5-year survival rate decreased from 92% to 10%.¹⁶⁰ The likelihood of recurrence and death is increased in the presence of pelvic lymph node metastasis and is related to the number of positive nodes.^{254, 255} In a series of 97 patients with stage IB–IIB carcinoma, one third of patients with one positive lymph node and two thirds with three or more positive nodes had recurrence of tumor within 5 years.²⁵⁹ In another study of stage I and II carcinomas, the rate of survival was 59% with unilateral and 20% with bilateral lymph node metastases.²⁵⁵ From the iliac lymph nodes, tumor may spread to involve paraaortic nodes, and, from there, the scalene nodes. Tumor involvement of these sites is associated with disseminated disease in more than 75% of patients.²⁶⁰ Paraaortic lymph node involvement is present in 6% of stage IB carcinoma and 30% of stage II and III disease.^{261, 262} When all series are combined, the overall incidence of scalene lymph node metastasis from cervical carcinoma is 15%.²⁶³

 

Table 5. Frequency of lymph node metastasis in surgically treated cervical carcinomas

LCK, large cell keratinizing; LCNK, large cell nonkeratinizing

 

Fig. 38. Metastatic squamous cell carcinoma in an iliac lymph node. The image shows a high-power view of clusters of malignant squamous cells within an iliac lymph node. (Hematoxylin-eosin stain, yellow bar: original magnification.)

 

 

 

 

Similar prognostic findings have been found in studies of patients who underwent radiation therapy. Barillot and colleagues²⁶⁴ reviewed 1875 women with cervical carcinoma treated by radiation therapy alone. By univariate analysis of stage I/II cases, FIGO stage, tumor diameter, and lymph node status were significant prognostic parameters. The 5-year survival rates were 83.5% for stage IB, 81% for stage IIA, 71% for stage IIB, 65% for stage IIIA, and 59% for stage IIIB. For tumors smaller than 3 cm, the 5-year survival rate was 86%, vs. 76% for tumors measuring 3–5 cm, and 61.5% for tumors >5 cm. By multivariate analysis, FIGO stage and nodal involvement remained significant for all stages. For stage I/II tumors, tumors larger than 5 cm and adenocarcinoma were poor prognosticators.²⁶⁴

Overall, most authors have agreed that the depth of stromal invasion, tumor dimension, the presence or absence of lymph-vascular space invasion, pelvic lymph node status, and parametrial involvement are important prognosticators. The value of classification by cell type and histologic grade continues to be controversial. While some authors have noted worse survival for women with adenocarcinoma and adenosquamous carcinoma compared with squamous cell carcinoma,^{246, 265} others have found no difference in survival for these three tumor types when compared stage by stage.^{264, 266} However, some specific tumor types have been more consistently associated with a more aggressive course. For example, studies on glassy cell carcinoma have shown a high frequency of pelvic and extrapelvic spread, poor response to surgery and/or radiotherapy, and 5-year survival rates in the range of 31–33%.²⁶⁷ This poor outcome is thought in part to be related to radioresistance and understaging of the tumor.²⁶⁷

A variety of growth patterns and stromal reactions have been described in cervical squamous cell carcinoma, but none are prognostically useful. Similarly, the results of vascular density counts are conflicting in relation to radiosensitivity of the tumor and prognosis. However, the newly proposed pattern-based classification system for cervical adenocarcinomas (discussed earlier in this chapter) appears to have some promise in predicting tumor behavior and prognosis.¹⁶⁴

Contradictory results have been reported for the prognostic significance of tumor grade. In surgically treated patients with stage I and II SCC, some studies have found histologic grade to influence prognosis and pelvic nodal metastasis.¹¹¹ In a study of stage I SCC from the GOG, the histologic grade was correlated with the frequency of pelvic nodal metastasis, which occurred in 9.7%, 13.9%, and 21.8% of grade 1, grade 2, and grade 3 tumors, respectively.¹¹¹ Comparable results were reported by Fuller and colleagues,²⁴⁷ who found that stage IB and IIA grade 3 tumors were larger and had a higher incidence of lymph node metastasis than lower-grade lesions.²⁴⁷ In their study, 25% of grade 3 tumors had pelvic lymph node metastases, compared with 9% and 16% of grade 1 and 2 tumors, respectively. The degree of differentiation in adenocarcinoma has also been demonstrated by some groups to be related to prognosis and pelvic nodal metastasis, with one study finding that in stage I and II tumors, pelvic nodal metastases were found in 5% of grade I, 11% of grade II, and 50% of grade III tumors.¹⁶⁰ Another study, however, showed that among 445 patients with stage IIB through IVA squamous cell carcinoma treated by radiation therapy following GOG protocols, the histologic grade had no impact on prognosis.¹¹² Similar findings were reported by others, including Sevin and associates.^{245, 252, 268} Of note, the newly proposed pattern-based classification system for adenocarcinoma (discussed above) also incorporates tumor grade, as pattern A tumors are defined as being well or moderately differentiated.¹⁶⁴

Tumor recurrence

 

Tumor recurrences are divided into three categories: central (involving vaginal cuff, bladder, or rectum), pelvic sidewall, and distant or extrapelvic. Tumor recurrence is reported to be central in 14–28%, sidewall or sidewall and central in 37–59%, and distant in 35–42% of cases.^{269, 270, 271} In a large study, 40 of 303 (13%) women with stage IB/IIB cervical cancers developed recurrence following radical hysterectomy and pelvic lymphadenectomy.²⁶⁹ In a literature review, tumor recurrence occurred within 12 months of initial treatment in 45–58% of cases, and within 3 years in 70–90% of cases.²⁶⁹ Pelvic recurrence may be asymptomatic and detected only on physical examination, or may be suspected by nonspecific symptoms such as vaginal bleeding or discharge. Pelvic sidewall recurrence may produce pain in the lower abdomen, back, hip, or leg. Distant metastases may present with pain or a mass lesion.

Usual sites of metastasis in cervical carcinoma include periureteral, abdominal, hepatic, and paraaortic regions. Spread to scalene node occurs via the thoracic duct. Unusual sites of recurrence, such as cutaneous lymphatic dissemination, are occasionally reported.²⁷²

Treatment with cisplatin-based combination chemotherapy and more recently with angiogenesis inhibitors (in particular bevacizumab) has been found to increase overall and progression-free survival and may be useful in recurrent or advanced stage cervical carcinoma.²⁷³

 

 

A variety of tumor antigens have been identified in cervical carcinoma using immunohistochemical techniques on tissue sections. Selected antigens with possible clinical utility are discussed here.

CEA is found in both squamous cell carcinoma and adenocarcinoma, as well as in normal cervical epithelium.²⁷⁴ In a series of 241 patients, 63% of large cell nonkeratinizing squamous carcinomas, 78% of keratinizing squamous carcinomas, 67% of small cell carcinomas, and 36% of adenocarcinomas were positive for CEA.²⁷⁵ The diagnostic utility of this antigen is limited, however, as it is found in benign, dysplastic, and malignant conditions. In addition, the presence of CEA in malignant tissue sections by itself has no prognostic significance.^{275, 276}

In the study of Borras and associates,²⁷⁷ serum tumor antigens were determined by immunoradiometric assay in 96 women with invasive carcinoma. Elevated levels of serum CEA, CA 19-9, and CA125 were found in 33%, 32%, and 21.5% of cases, respectively. Increased CEA and CA 19-9 were related to clinical stage. Serum CA125 and CA 19.9 were higher in patients with adenocarcinoma than squamous cell carcinoma. When disease free, these antigens tended to decrease. All progressive cases had an elevated level of one of these antigens.²⁷⁷ Thus, as serum markers, these antigens are useful for monitoring tumor recurrence, especially for adenocarcinoma. Preoperative levels of CA125 have also been found to correlate with tumor size, depth, lymph-vascular space invasion, and lymph node metastasis.²⁷⁸

Squamous cell carcinoma antigen is one of 14 subfractions of the TA-4 tumor antigen, isolated in 1977 from cervical squamous cell carcinoma by Kato and Torigoe.²⁷⁹ Like CEA, SCC antigen can be demonstrated in both benign and malignant cervical epithelium, and increased serum levels occur almost exclusively in cancer patients.²⁸⁰ In a study of 96 cervical carcinoma patients who had increased serum levels of SCC antigen at the time of diagnosis, persistently high levels following completion of radiotherapy were significantly associated with biopsy-proven residual disease. In 60% of patients with persistently high SCC antigen levels, residual tumor was found on cervical biopsy.²⁸¹ SCC antigen levels have also been found to be predictive of recurrence, with one study finding that 81% of patients with recurrent cervical squamous cell carcinoma had elevated SCC antigen levels.²⁸² Additionally, preoperative serum SCC antigen levels have been found to be predictive of tumor size, depth, lymph-vascular space invasion, and lymph node metastasis.²⁷⁸

Cytokeratins may also be useful serum biomarkers in cervical cancer. Elevated pretreatment levels of serum fragments of cytokeratin 19 (CYFRA) have been correlated with higher stage, tumor size, lymph node metastasis, and depth of invasion.^{283, 284} CYFRA levels may also be a useful measure of treatment response to radiation.²⁸⁵One recent study reported CYFRA 21-1 levels to be an independent predictor of overall survival in squamous cell carcinomas and non-squamous cell carcinomas of the cervix.²⁸³

Mandai and associates²⁸⁶ used immunohistochemical stains to examine the expression of nm23-H1 and c-erb-2 proteins. The nm23-H1 gene was originally cloned from murine melanoma cell lines with low and high metastatic potential. It was identified later in humans. nm23-H1 expression is associated with a better prognosis and lower rates of lymph node metastasis in breast ductal carcinoma, hepatocellular carcinoma, and gastric carcinoma patients.²⁸⁶ c-erbB-2 (HER2/neu), a member of the epidermal growth factor receptor family, when overexpressed, is associated with poor prognosis in breast carcinoma. In the study of Mandai and associates, nm23-H1 was expressed in 46% of cervical adenocarcinomas and 36% of squamous cell carcinomas, and c-erb-2 was overexpressed in 49% of cervical adenocarcinomas and 38% of squamous cell carcinomas. A negative nm23-HI and an overexpressed c-erb-2 were associated with increased lymph node metastasis and poor prognosis in adenocarcinoma. These findings were not applicable to squamous cell carcinoma.²⁸⁶ Other groups have found that the rate of c-erbB-2 amplification and overexpression in cervical carcinomas is extremely low, arguing against its potential utility.²⁸⁷

A number of hypoxia and angiogenesis-related factors have also been studied as potential biomarkers in cervical cancer. These include HIF-1ɑ, VEGF, and CA9. One study of 67 patients who had received radiation therapy for cervical cancer found HIF-1ɑ immunohistochemical expression to be a predictor of only partial response to therapy, shorter progression-free survival, and shorter disease-specific survival.²⁸⁸ Another study also found HIF-1ɑ to be an independent predictor of overall survival.²⁸⁹ Immunohistochemical expression of VEGF is also reported to be an independent predictor of survival,²⁹⁰ and immunohistochemical expression of CA9 is associated with lymph node metastasis and a worse disease-free survival,²⁹¹ as well as worse overall survival following radiation therapy.²⁹²

The apoptotic marker COX-2 has also been studied, immunohistochemical expression of which has been associated with lymph-vascular space invasion, poor treatment response, and decreased overall and progression-free survival.^{293, 294, 295} A greater association with adenocarcinoma vs. squamous cell carcinoma is also reported.^{293, 295}

The role of oncogenes in cervical carcinoma has also been investigated. Mutations and overexpression of both the c-myc and ras oncogenes have been demonstrated in cervical carcinoma.^{296, 297, 298, 299} Some studies have correlated the degree of abnormal expression with prognosis. In one study, expression of the c-myc oncogene was increased in 25 of 72 stage I and II cervical carcinomas, and was associated with an eightfold or higher increase in the rate of early relapse in these patients.²⁹⁹

Estrogen and progesterone receptors have been detected in both benign and malignant cervical epithelia.^{300, 301} While the techniques used to detect these receptors vary among studies, most investigators have found no prognostic significance of the level of estrogen or progesterone receptors in cervical squamous cell carcinoma. In a study of 70 cases, Hunter and colleagues³⁰⁰ found no significant correlation between steroid receptors and a variety of parameters, including stage, menopausal status, cell type, histologic grade, or survival.

Flow cytometric analysis of cervical squamous cell carcinoma has been carried out by numerous investigators, and the results concerning the prognostic significance of DNA ploidy and S-phase rates in cervical carcinoma have been conflicting. Aneuploidy has been found in 28–44% of cervical carcinomas,³⁰² with some authors finding this factor to be predictive of a worse overall survival³⁰³and correlated with a higher stage.³⁰⁴ Similarly, some groups have found high S-phase rates to be associated with early recurrence,³⁰⁵ and aggressive histopathologic features (infiltrative growth pattern, vascular invasion, sparse lymphoplasmacytic infiltrate).³⁰⁴ Others, however, have found that DNA ploidy and S-phase rates do not correlate with recurrence or survival.^{306, 307, 308}

This review of biomarkers is far from comprehensive, and the reader is referred to several excellent recent reviews on the subject for further information.^{302, 309, 310}

 

Updated screening guidelines

The advent of screening programs for cervical cancer using cervical cytology (Papanicolaou smear) in the mid-1900s has significantly reduced the mortality of cervical cancer worldwide, particularly in developed countries.³¹¹ HPV testing has greater sensitivity than does cytology for the diagnosis of cervical intraepithelial lesions,³¹² and its addition to screening programs allows for consideration of longer screening intervals, and also provides the advantage of detecting more glandular lesions. In 2012, the American Society for Colposcopy and Cervical Pathology (ASCCP), along with the American Cancer Society (ACS) and American Society for Clinical Pathology (ASCP), updated their guidelines for cervical cancer screening.³¹³ The highlights of the current guidelines are summarized below.

Screening for cervical cancer is recommended to begin at 21 years of age. This does not represent a change in the previous guidelines, and is based on the rarity of cervical carcinoma in patients younger than 21 and the potential for overtreatment and harm if these young patients are screened.³¹³

For women ages 21–29 years, screening is recommended with cytology alone every 3 years. HPV testing is not recommended for screening in these patients. The lengthening of the screening interval, which was originally only 1 year, is based on the very small increase in cancers prevented by shorter screening intervals compared with the harm of overtreating patients whose HPV-associated lesions may yet regress. The prevalence of HPV infection is high in this age group, and as most of these infections will regress, screening with HPV testing is not recommended.³¹³

For women ages 30–65 years, screening with both cytology and HPV testing (“cotesting”) every 5 years is recommended, but screening with cytology alone every 3 years is also considered acceptable. The justification for the longer interval for cotesting is based on the increased sensitivity for CIN 3 detection afforded by the addition of HPV testing, resulting in a lower subsequent risk of cervical carcinoma following negative cotesting vs. negative cytology alone.³¹³

The 2012 recommendations did not endorse primary screening via HPV testing alone, due to concerns regarding the lower specificity of HPV testing vs. cytology, the lack of data on cytology as a follow-up test, and the possibility of unrecognized specimen inadequacy as a cause for false negative HPV tests.³¹³ However, in 2014, the United States Food and Drug Administration (FDA) approved the Cobas HPV test manufactured by Roche Molecular Systems for primary cervical cancer screening.³¹⁴ It is expected that new screening guidelines addressing this will be forthcoming in the next few years.

Also of note, the 2012 recommendations do not advocate any change in screening practices based on the introduction of the HPV vaccine (discussed below), due to as yet limited data as well as limited vaccine uptake in the United States.³¹³

Updated management guidelines were also put forth by the ASCCP in 2012, and the reader is referred to the relevant publications for further details of both screening and management.^{33, 313}

The cervical cancer screening recommendations in the 2014 Guide to Preventive Services, put forth by the United States Preventive Services Task Force (USPSTF), are very similar to the current ASCCP guidelines, including the initiation of screening at age 21 years, the use of cytology for screening every 3 years in women age 21–65 years, and the acceptability of cotesting every 5 years for women age 30–65 years.³¹⁵ The ASCCP screening guidelines have also been endorsed by the American College of Obstetricians and Gynecologists (ACOG).³¹⁶

HPV vaccine

In 2006, the US FDA approved the first vaccine against HPV, Gardasil, for use in women ages 9–26 years as a three-injection protocol. The original Gardasil, manufactured by Merck, is a quadrivalent vaccine covering HPV types 6, 11, 16, and 18.³¹⁷ In 2009, the bivalent vaccine Cervarix, manufactured by GlaxoSmithKline and covering HPV types 16 and 18, was also approved for use in women age 10–25 years.³¹⁸ More recently, in December of 2014, the FDA approved the new 9-valent Gardasil, covering HPV types 16, 18, 31, 33, 45, 52, 58, 6, and 11, with the potential to prevent 90% of cervical, vulvar, vaginal, and anal cancers.³¹⁹ Currently, HPV vaccination is recommended for females ages 9–26 years, with several countries (including the United States, Canada, Austria, and Australia) also recommending vaccination for males to protect against genital warts, prevent HPV infection in their sexual partners, and reduce the incidence of anal cancer in men who have sex with men (MSM).³²⁰

Vaccination against HPV has been demonstrated to have excellent efficacy. One large, randomized, placebo-controlled study from Australia involving 5455 women found an efficacy of 100% for the quadrivalent vaccine in the prevention of genital warts, vulvar/vaginal intraepithelial lesions or cancer, and cervical intraepithelial lesions or cancer associated with the four covered HPV types.³²¹ In the same study, an intention-to-treat analysis found that the vaccine reduced the rate of any cervical lesions (including those related to non-covered HPV types) by 20%.³²¹ Australia’s HPV vaccination program has been very successful, with an impressive decrease in the prevalence of the covered HPV types in the 4 years following initiation of their national vaccination program (6.7% post-vaccine vs. 28.7% pre-vaccine).³²² Vaccine uptake in the United States has been much lower than in many other developed nations, with 57.3% of adolescent females (13–17 years) and 34.6% of adolescent males receiving at least one dose in 2013, and only 37.6% of adolescent females and 13.9% of adolescent males receiving three doses in 2013.³²³ Even so, the vaccine has proven effective in vaccinated individuals, with a significant decrease in the prevalence of HPV 16/18-related HSIL in women who received at least one dose (53.6% in 2008 vs. 28.4% in 2012).³²⁴

The protective effect of the vaccine against the covered HPV types has been demonstrated for at least 8 years after complete vaccination,³²⁰ and there is some cross-protection against non-covered HPV types.^{325, 326, 327, 328} It has been demonstrated that in women with HPV infection by 1 or more of the covered HPV types at the time of vaccination, the vaccine is still 100% effective at preventing lesions caused by the remaining covered HPV types.³²⁹ Additionally, the vaccine also provides protection against reinfection or reactivation by covered HPV types in women with evidence of past infection by one or more of these HPV types.³³⁰ Despite some controversy, particularly from a number of political groups in the United States, the safety of the vaccine has been demonstrated in numerous large studies.^{331, 332}

Currently, therapeutic vaccination against HPV-associated lesions is under investigation. These vaccines are targeted against E6 and E7 viral peptides, with promising results from phase I and II testing, and phase III testing planned for 2016.^{333, 334, 335, 336, 337}

 

Optimal management of cervical cancer patients requires accurate assessment of the quality and the quantity of the neoplasm. Proper handling of the surgical specimens allows for comprehensive reporting of prognostically important pathologic findings. The use of immunohistochemistry and other techniques further enhances the validity of diagnosis and prognosis.