Vulvar Acanthosis With Altered Differentiation

TP53 Wild-Type, Human Papillomavirus-Independent Anal Growth/(Intra)Epithelial Lesion (ANGEL): A Potential Precursor of Anal Squamous Cell Carcinoma

Human papillomavirus (HPV) underpins ∼90% of squamous cell carcinomas (SCCs) of the anus and perianal region. These tumors usually arise in association with precursor lesions such as anal intraepithelial neoplasia/high-grade squamous intraepithelial lesion, whereas a small subset of HPV-negative cancers may harbor mutations in TP53. Recently, vulvar lesions termed differentiated exophytic vulvar intraepithelial lesion/vulvar acanthosis with altered differentiated have been recognized as HPV-independent, TP53 wild-type precursors for vulvar carcinoma; however, analogous anal lesions have not been described. Cases of diagnostically challenging, TP53 wild-type HPV-negative anal squamous lesions with unusual histologic features including acanthosis and/or verrucous architecture were retrospectively identified. Lesions with koilocytic changes, lack of surface maturation, or significant cytologic atypia were excluded. HPV status was determined by immunohistochemistry for p16 and/or in situ hybridization for low- and high-risk strains, whereas TP53 status was assessed using immunohistochemistry and molecular studies in a subset of cases, with targeted molecular sequencing performed in 3 of these. All lesions (5/5) arose in men, ages ranging from 55 to 78 years (median: 65 years). Verrucous architecture was seen in 2 of 5 cases, 2 of 5 were predominantly acanthotic, and 1 of 5 had both verrucous and acanthotic growth. The lesions were characterized by hyperkeratosis (5/5), hypergranulosis (5/5), and cytoplasmic pallor of upper epithelial layers (2/5). All cases were negative for HPV and had wild-type p53 expression. Three cases with sufficient material for sequencing lacked alterations within the entire coding sequencing of TP53. Invasive SCC was concurrently present in 3 of 5 cases. In summary, verrucous and acanthotic HPV-independent TP53 wild-type squamous proliferation of the anal and perianal region, referred to herein as anal growth/(intra)epithelial lesion (ANGEL), are premalignant lesions that have the potential to become invasive, as most of our cases demonstrated synchronous SCC.

Verruciform Acanthotic Vulvar Intraepithelial Neoplasia Harbors Recurrent Genomic Alterations Found in HPV-independent Squamous Cell Carcinoma

The term verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN) was coined to describe HPV-independent p53-wildtype lesions with characteristic clinicopathologic characteristics and association with vulvar squamous cell carcinoma (vSCC). We aimed to expand on the molecular landscape of vaVIN using comprehensive sequencing and copy number variation profiling. vaVIN diagnosis in institutional cases was confirmed by a second review, plus negative p16 and wildtype p53 by immunohistochemistry. Multigene next-generation sequencing and shallow-whole genome sequencing were used to survey for single-nucleotide variants (SNV), copy number alterations, and structural variants. Targeted TERT promoter sequencing was also carried out. Nineteen patients with vaVIN were included; 4 had concurrent vSCC. The median patient age was 74 (range 56-90) years. Genomic aberrations were noted in 18 cases (95%) as follows: PIK3CA in 10 (53%), CDKN2A in 7 (37%), HRAS in 6 (32%), FAT1 and NOTCH1-2 in 5 each (26%), TSC2 in 2 (11%), and PTEN, ARID2, and KRAS in 1 (5%) each. TERT promoter variants were detected in 11 of 13 cases successfully tested (85%). Five vaVINs harbored a TP53 variant but showed wild-type p53 immunohistochemical expression. In one of these, the concurrent carcinoma showed abnormal p53 and biallelic TP53 mutations. Out of 15 patients with follow-up (mean: 20, range: 2-50 mo), vaVIN persistence/recurrence was seen in 8 (53%), and subsequent vSCC in 2 (13%). At the last encounter, 3 (20%) patients had persistent disease and 1 (7%) died of vSCC. vaVIN is characterized by a wider molecular spectrum, beyond known alterations in PIK3CA, HRAS, and ARID2, to include TERT promoter, CDKN2A, FAT1, and NOTCH1-2, which are characteristic of HPV-independent vSCC. vaVIN can occur with concurrent or subsequent carcinoma, sometimes with fatal outcomes. These findings support the concept of vaVIN as a neoplastic process within the family of HPV-independent vulvar neoplasia.

Vulvar Cancer: Histopathologic Considerations and Nuances to Management

Vulvar cancer, although rare, poses significant challenges in diagnosis and treatment because of its histopathologic complexities and nuances. This paper reviewed key aspects of the management of vulvar cancer, focusing on histopathologic diagnosis, margin status interpretation, lymph node involvement assessment, and ongoing clinical trials.

Precancerous Lesions of HPV-independent Vulvar Squamous Cell Carcinoma: Clinicopathologic Consideration of an Evolving Spectrum

HPV-independent squamous cell carcinomas of the vulva comprise the majority of vulvar cancers, but their putative precancers represent only a small proportion of the vulvar squamous intraepithelial lesions that are encountered in routine practice. The precancerous lesions of HPV-independent vulvar squamous cell carcinoma encompass a spectrum of lesions that, collectively, may pose significant diagnostic challenges. Included in this spectrum are differentiated vulvar intraepithelial neoplasia [dVIN], the prototypical lesion of the group, which is characterized by a high propensity for progression, a relatively short duration to progression, frequent association with lichen sclerosus, and according to our review of the recent literature, TP53 /p53 aberration in 50% to 95% (mean 77.4%) of cases. Regarding the latter, some authors consider TP53 /p53 aberration to be a diagnostic requirement for dVIN, although this is controversial, as discussed further herein. Also included in the spectrum of lesions that are considered in this review are possibly related HPV-independent, p53-wild type lesions that have historically been reported as "vulvar acanthosis with altered differentiation" (VAAD), "differentiated exophytic vulvar intraepithelial lesion" (DEVIL), "verruciform lichen simplex chronicus" (vLSC), and which more recently, have collectively been described as "verruciform acanthotic vulvar intraepithelial neoplasia (vaVIN)" or "vulvar aberrant maturation (VAM)." In this review, we perform a comprehensive clinicopathologic review of putative precancerous lesions of HPV-independent squamous cell carcinomas of the vulva, with an emphasis on recent developments in terminology, practical diagnostic issues, biomarkers, and pathogenesis.

Typing of Vulvar Squamous Cell Carcinoma: Why it is Important?

The classification of vulvar squamous cell carcinoma (VSCC), as in endometrial cancer, has shifted from the histology-based descriptors toward molecular-based identifiers. Recently, it has been reported that there are 3 genetically distinct and clinically significant subtypes of VSCC: HPV-associated VSCC, HPV-independent/p53 wild-type VSCC, and HPV-independent/p53-mutated VSCC. Each group has different prognostic implications as well as response to treatment, thus reinforcing the need for this 3-tier molecular classification. This molecular subtyping can easily be done on vulvar biopsies using p16 and p53 immunohistochemistry stains to further improve risk prediction and individualized treatment decisions, leading to better patient outcomes.

PD-L1 Expression in HPV-associated Versus HPV-independent Invasive Vulvar Squamous Cell Carcinoma

Two etiological pathways have been implicated in the pathogenesis of vulvar squamous cell carcinoma (VSCC): a high-risk human papillomavirus (HPV)-associated route and an HPV-independent pathway characterized by TP53 mutations. Programmed cell death ligand 1 (PD-L1) has become increasingly useful in predicting the response to checkpoint inhibitor therapy in squamous cell carcinomas at various anatomical sites. This study aimed to assess the association between PD-L1 expression and the VSCC subtype to evaluate the utility of PD-L1 in prognostication and therapeutic selection based on HPV status. PD-L1 status was assessed using 3 separate metrics for the extent of PD-L1 staining in various cell types: immune cell score, tumor proportion score (TPS), and combined positive score. The study group consisted of 25 HPV-associated and 28 HPV-independent VSCCs. PD-L1 expression was positive in the majority of VSCCs according to all 3 scoring metrics (84.9% by immune cell score, 77.3% by TPS, and 90.6% by combined positive score). PD-L1 expression was observed in the majority of cases in both groups (60%-96.4%). PD-L1 expression using the TPS method was greater in HPV-independent tumors than in HPV-associated tumors ( P = 0.004), and high PD-L1 expression was also more common in the HPV-independent subtype ( P = 0.016 using the TPS method and P = 0.013 using the combined positive score method). Our findings contribute to the growing evidence that PD-L1 is expressed in the majority of invasive VSCCs, and thus may serve as an attractive therapeutic target. PD-L1 expression is higher in HPV-independent tumors, suggesting that this subtype may be more responsive to PD-L1 inhibitor therapy.

Diagnosis of verruciform acanthotic vulvar intra-epithelial neoplasia (vaVIN) using CK17, SOX2 and GATA3 immunohistochemistry

AIMS

Verruciform acanthotic vulvar intra-epithelial neoplasia (vaVIN) is an HPV-independent, p53 wild-type lesion with distinct morphology and documented risk of recurrence and cancer progression. vaVIN is rare, and prospective distinction from non-neoplastic hyperplastic lesions can be difficult. CK17, SOX2 and GATA3 immunohistochemistry has emerging value in the diagnosis of HPV-independent lesions, particularly differentiated VIN. We aimed to test the combined value of these markers in the diagnosis of vaVIN versus its non-neoplastic differentials in the vulva.

METHODS AND RESULTS

CK17, SOX2 and GATA3 immunohistochemistry was evaluated on 16 vaVINs and 34 mimickers (verruciform xanthoma, lichen simplex chronicus, lichen sclerosus, psoriasis, pseudo-epitheliomatous hyperplasia). CK17 was scored as 3+ = full-thickness, 2+ = partial-thickness, 1+ = patchy, 0 = absent; SOX2 as 3+ = strong staining ≥ 10% cells, 2+ = moderate, 1 + =weak, 0 = staining in < 10% cells; and GATA3 as pattern 0 = loss in < 25% basal cells, 1 = loss in 25-75% basal cells, 2 = loss in > 75% basal cells. For analysis, results were recorded as positive (CK17 = 3+, SOX2 = 3+, GATA3 = patterns 1/2) or negative (CK17 = 2+/1+/0, SOX2 = 2+/1+/0, GATA3 = pattern 0). CK17, SOX2 and GATA3 positivity was documented in 81, 75 and 58% vaVINs, respectively, versus 32, 17 and 22% of non-neoplastic mimickers, respectively; ≥ 2 marker positivity conferred 83 sensitivity, 88 specificity and 86% accuracy in vaVIN diagnosis. Compared to vaVIN, SOX2 and GATA3 were differentially expressed in lichen sclerosus, lichen simplex chronicus and pseudo-epitheliomatous hyperplasia, whereas CK17 was differentially expressed in verruciform xanthoma and adjacent normal mucosa.

CONCLUSIONS

CK17, SOX2 and GATA3 can be useful in the diagnosis of vaVIN and its distinction from hyperplastic non-neoplastic vulvar lesions. Although CK17 has higher sensitivity, SOX2 and GATA3 are more specific, and the combination of all markers shows optimal diagnostic accuracy.

Updates in the Use of Immunohistochemical Stains in Breast and Gynecologic Pathology

CONTEXT.—

The use of immunohistochemical stains in breast and gynecologic pathology has become increasingly complex, with various diagnostic, prognostic, and predictive applications.

OBJECTIVE.—

To provide an update and review of immunohistochemical stains used in the practice of breast and gynecologic pathology. Established and new entities are reviewed, with descriptions of histomorphology and immunohistochemical staining patterns and discussion of interpretive pitfalls.

DATA SOURCES.—

Data were obtained from review of the English-language literature and firsthand experience of the authors in breast and gynecologic pathology.

CONCLUSIONS.—

Many entities in breast and gynecologic pathology benefit from evaluation with various immunohistochemical stains. These studies not only aid in the diagnosis and staging of tumors but also can provide prognostic and predictive information. Updated guidelines for recommended ancillary studies such as mismatch repair, p53, and human epidermal growth factor receptor 2 (HER2) studies in endometrium, as well as estrogen and progesterone receptors and HER2 in breast, are discussed. Finally, the use and interpretation of established and novel immunohistochemical stains are discussed in various breast and gynecologic malignancies.

The Spectrum of HPV-independent Penile Intraepithelial Neoplasia: A Proposal for Subclassification

Compared with vulva, precursor lesions of human papillomavirus (HPV)-independent invasive squamous cell carcinoma (SCC) of the penis are insufficiently characterized. We analyzed the histologic and immunohistochemical characteristics of 70 peritumoral precursor lesions and correlated them with the histology and mutational profile of the adjacent HPV-negative invasive penile SCC. Atypical basal keratinocyte proliferation with variously elongated epithelial rete with premature squamatiziation, but regular superficial cornification, termed differentiated penile intraepithelial neoplasia (d-PeIN), were identified adjacent to 42/70 (60%) SCC (36/42 keratinizing ( P <0.001); 3 papillary, and 1 each verrucous, clear cell, sarcomatoid SCC). d-PeIN were associated with chronic inflammatory dermatoses (32/42; P <0.001), p53 overexpression (26/42; P <0.001), and hotspot mutations in TP53 (32/42; P <0.001), CDKN2A (26/42; P <0.001) or both (21/42; P =0.003) in the adjacent SCC. Cytoplasmic p16 ink4a overexpression in 5/42 d-PeIN correlated with CDKN2A missense mutations in the adjacent SCC. In all, 21/70 (30%) cornified verrucous or glycogenated verruciform precursors with minimal atypia and wild-type p53 (18/21; P <0.001) occurred adjacent to verrucous or papillary SCC (17/21; P <0.001) and keratinizing (4/21) SCC, which harbored mutations in HRAS and/or PIK3CA (12/21; P <0.004). Undifferentiated p16 ink4a -negative full-thickness precursors were identified in 7/70 (10%) SCC. Four histologically different HPV-independent penile precursor lesions can be assigned to 2 major genetic/biological pathways with characteristic highly differentiated precursors requiring different clinical management decisions. These include d-PeIN in chronic inflammatory dermatoses, with p53 overexpression and TP53/CDKN2A mutations, and the p53 wild-type verrucous and verruciform precursors unassociated with dermatoses, but with mutations in oncogenes PIK3CA and HRAS .

Interobserver Agreement Across Subspecialties for Diagnosis of Differentiated Vulvar Intraepithelial Neoplasia and Predictive Values of 20 Histologic Features

CONTEXT.—

Differentiated vulvar intraepithelial neoplasia (dVIN) is a human papillomavirus-independent lesion with the potential for rapid progression to invasive squamous cell carcinoma (SCC). The histopathologic features of dVIN are diverse, have overlapping characteristics with lichen sclerosus (LS) and lichen simplex chronicus (LSC), and may be diagnosed by dermatopathologists or gynecologic pathologists because of the vulva's anatomic location.

OBJECTIVES.—

To identify the salient histopathologic features of dVIN, particularly those that predict progression to SCC, and to evaluate interobserver agreement in diagnosing dVIN within the same subspecialty and across subspecialties.

DESIGN.—

One general surgical pathologist, 2 pathology-trained dermatopathologists, and 1 gynecologic pathologist blinded to the final diagnoses were asked to record 20 histopathologic features and to provide their final interpretations on cases of dVIN (n = 65), LS (n = 126), LSC (n = 112), and LS with LSC (n = 6).

RESULTS.—

Interobserver agreement for the 4 diagnoses and 10 histopathologic features was moderate. Logistic regression analysis indicated that keratin pearls, basal pleomorphism, and basal layer disarray were independent variables for diagnosing dVIN (coefficients 1.95, 1.97, and 0.91, respectively; P < .001) and progression to SCC (coefficients 1.96, 1.20, and 1.08, respectively; P < .001).

CONCLUSIONS.—

There is no single histopathologic feature pathognomonic for dVIN; however, the presence of keratin pearls, basal pleomorphism, and basal layer disarray should raise high suspicion for dVIN and concurrent SCC. Expertise in both dermatologic and gynecologic pathology is beneficial for diagnosing dVIN.

Betapapillomaviruses in p16-Negative Vulvar Intraepithelial Lesions Associated with Squamous Cell Carcinoma

Approximately 40% of vulvar squamous cell carcinoma (vSCC) cases are etiologically associated with high-risk human papillomaviruses (HPVs) of the alpha genera (α-HPV) that cause other anogenital cancers; however, the etiology of α-HPV-negative vSCC is poorly understood. HPVs of the beta genera (β-HPV) are risk factors for cutaneous squamous cell carcinoma (cSCC) and may be related to carcinomas originating in other cutaneous sites such as the vulva. In this study, we investigate the presence of β-HPVs, with an emphasis on p16-negative squamous lesions adjacent to vSCC. We subjected 28 vulvar squamous intraepithelial lesions adjacent to vSCC for comprehensive HPV genotyping, p16 and p53 immunohistochemistry, and consensus morphology review. Selected cases were subjected to qPCR and RNA in situ hybridization. Clinical data were obtained from medical records. β-HPV DNA was detected in eight of ten p16-negative lesions and three of fourteen p16-positive high-grade squamous intraepithelial lesions. The HPV DNA loads in vulvar squamous intraepithelial lesions ranged between less than 1 HPV DNA copy per cell to more than 100 HPV DNA copies per cell. This is, to the best of our knowledge, the first report of the association of p16-negative vulvar intraepithelial squamous lesions with detection of β-HPVs. These findings expand possible etiologic mechanisms that may contribute to p16-negative lesions of the vulva.

Precursors, pathways of carcinogenesis and molecular markers of vulvar squamous cell carcinoma. Literature review

The review analyzes and summarizes the results of the studies on the pathogenesis of  vulvar squamous cell carcinoma and its diagnostic features, reviews precursors and  molecular subtypes of carcinomas. Despite the relatively low incidence of this tumor, over the past few decades, there has been an upward trend in its incidence, including the incidence among young women. According to the latest World Health Organization classification of lower genital tumors from 2020, vulvar squamous cell carcinoma is divided into human papillomavirus (HPV) associated and HPV-independent. While these carcinomas are often morphologically similar, their mechanisms of carcinogenesis, precursors, and clinical outcomes are different. Just the detection of virus DNA in a tumor is not enough to establish HPV status. Meanwhile immunohistochemical detection of the expression of p16 and p53 proteins allows not only to separate two pathogenetic pathways of carcinogenesis, but also to identify its molecular subtypes. The data on the possible use of p16 and p53 expression as the disease prognosis molecular markers have been obtained. Currently, the tactics of treatment and monitoring patients does not depend on the HPV status of carcinoma; however, the results of recent studies suggest that women with HPV positive vulvar cancer have significantly higher survival rates and a lower risk of recurrence. Understanding the mechanisms of carcinogenesis and improving its diagnosis will advance the assessment of the individual risk of the progression of precancerous lesions, as well as the outcome and the occurrence of tumor recurrence. 

MTA1 as negative prognostic marker in vulvar carcinoma

PURPOSE

Vulvar cancer is the fourth most common malignancy of the female genital tract after endometrial, ovarian, and cervical carcinoma and affects mainly elderly women. In 2020 there were registered more than 17,000 deaths worldwide related to vulvar carcinoma. Data about target-based therapies and predictive biomarkers for vulva carcinomas are rare so far. The metastasis-associated gene MTA1 is a transcriptional repressor with a potential effect on cancer. Expression of MTA1 was found to be significantly enhanced in gynecological malignancies as breast or ovarian cancer tissues with advanced cancer stages and higher FIGO grading, indicating an important role of MTA1 in the progression of those tumor entities. Due to the lack of information around MTA1 and its significance regarding vulvar carcinoma, this study focuses on the expression of MTA1 in vulvar carcinoma and its correlation to clinicopathological characteristics and prognosis.

METHODS

A total of 157 paraffin-embedded vulvar cancer tissues were immunohistochemically stained and examined for MTA1 expression by using the immunoreactive score. Subsequently, the values were correlated with clinicopathological parameters.

RESULTS

MTA1 was found to be expressed in 94% of the patients in the cytoplasm and 91% in the nucleus. Cytoplasmatic expression of MTA1 was significantly increased in non-keratinizing squamous cell carcinoma and in vulvar carcinoma of the condylomatous type, compared to keratinizing squamous cell carcinoma and vulvar carcinoma of the verrucous type. High MTA1 expression in the nucleus was associated with advanced tumor size as well as higher FIGO grading. In addition, p16 negative vulvar carcinomas showed a higher nuclear expression of MTA1 compared to p16 positive vulvar carcinomas. Suprisingly, Kaplan-Meier analysis showed a significantly lower disease-free survival in tumor samples without a nuclear expression of MTA1.

CONCLUSIONS

MTA1 was identified as a negative prognostic marker for vulvar carcinoma associated with advanced tumor stage and FIGO grading. A possible explanation could be that the antibody used for this study does not bind to a possible mutation in the C terminal region of MTA leading to negative immunohistochemical staining and this can be correlated with early recurrence in patients with vulvar carcinoma.

Molecular Features of Preinvasive and Invasive Vulvar Neoplasms

OBJECTIVES

Neoplasms arising from the vulva are uncommon and comprise various subtypes. Given the recent advancements in the molecular aspects of oncologic pathology and how they have impacted cancer treatment, an understanding of recent innovations in the molecular features of vulvar lesions is important.

MATERIALS AND METHODS

Systematic literature search was performed on PubMed, Google Scholar, and Scopus databases for molecular and genetic characteristics of vulvar neoplasms. Peer-reviewed literature published in English is included.

RESULTS

Squamous cell carcinoma (SCC) and its precursors are the predominant neoplasm at this site. Human papillomavirus (HPV) plays a crucial role in the pathogenesis of some of these lesions. Human papillomavirus-associated SCC follows the carcinogenic pathway driven by viral proteins E6 and E7 while HPV-independent SCC shows a high incidence of mutation of TP53 and CDKN2A genes. Mutations in the genes involving the PI3K-Akt pathway play an important role in the pathogenesis of both types of SCC. Among other vulvar malignancies, melanoma, and vulvar Paget disease (VPD) pose a significant clinical challenge and have unique molecular characteristics. Compared with dermal cutaneous melanoma, vulvar melanoma shows a higher rate of mutation of cKIT and NRAS genes and a lower rate of mutations in BRAF . Less than 20% of VPD shows amplification of ERBB2 and seldom shows mutation in genes involving the PI3K-Akt pathway.

CONCLUSIONS

Several potentially targetable molecular pathways have emerged as they have been shown to be involved in the tumorigenesis of SCC, melanoma, and VPD.

HPV-independent, p53-wild-type vulvar intraepithelial neoplasia: a review of nomenclature and the journey to characterize verruciform and acanthotic precursor lesions of the vulva

Vulvar squamous cell carcinomas and their precursors are currently classified by the World Health Organization based on their association with high-risk human papillomavirus (HPV). HPV independent lesions often harbor driver alterations in TP53, usually seen in the setting of chronic vulvar inflammation. However, a group of pre-invasive vulvar squamous lesions is independent from both HPV and mutant TP53. The lesions described within this category feature marked acanthosis, verruciform growth and altered squamous maturation, and over the last two decades several studies have added to their characterization. They have a documented association with verrucous carcinoma and conventional squamous cell carcinoma of the vulva, suggesting a precursor role. They also harbor recurrent genomic alterations in several oncogenes, mainly PIK3CA and HRAS, indicating a neoplastic nature. In this review, we provide a historical perspective and a comprehensive description of these lesions. We also offer an appraisal of the terminology used over the years, going from Vulvar Acanthosis with Altered Differentiation and Verruciform Lichen Simplex Chronicus to Differentiated Exophytic Vulvar Intraepithelial Lesion and Vulvar Aberrant Maturation, the latter term having been recently proposed by the International Society for the Study of Vulvovaginal Diseases. In line with the recognition of these lesions by the 2020 World Health Organization Classification of Tumours as a neoplastic precursor, we herein propose the term HPV-independent, p53-wild-type verruciform acanthotic Vulvar Intraepithelial Neoplasia (HPVi(p53wt) vaVIN), which better conveys not only the pathology but also the neoplastic nature and the biologic risk inherent to these uncommon and challenging lesions. We outline strict morphologic and immunohistochemical criteria for its diagnosis and distinction from mimickers. Immunohistochemistry for p16 and p53 should be performed routinely in the diagnostic work-up of these lesions, and the morphologic alternative term vaVIN should be reserved for instances in which p16/HPV/p53 status is unknown. We also discuss management considerations and the need to further explore precursors within and beyond the spectrum of verruciform acanthotic vulvar intraepithelial neoplasia.

Squamous and Glandular Lesions of the Vulva and Vagina: What's New and What Remains Unanswered?

A number of changes have been introduced into the 5th Edition of the World Health Organization (WHO) Classification of squamous and glandular neoplasms of the vulva and vagina. This review highlights the major shifts in tumor classification, new entities that have been introduced, recommendations for p16 immunohistochemical testing, biomarker use, molecular findings and practical points for pathologists which will affect clinical care. It also touches upon several issues that still remain answered in these rare but undeniably important women's cancers.

Molecular landscape of vulvovaginal squamous cell carcinoma: new insights into molecular mechanisms of HPV-associated and HPV-independent squamous cell carcinoma

Squamous cell carcinomas of the lower female genital tract may be human papillomavirus-associated or independent. We studied the HPV status, mutational repertoire, histology, and clinical data of 28 samples from 26 patients, 65% with a vulvar primary and 35% with a vaginal primary. These represented invasive vulvovaginal squamous cell carcinomas that underwent clinical tumor-normal targeted massively parallel sequencing analysis. HPV status was determined using the HPV high-risk RNA ISH assay and/or by MSK-IMPACT. Eleven patients had HPV-associated squamous cell carcinoma (four vulvar and seven vaginal) and 15 patients had HPV-independent SqCC (13 vulvar and 2 vaginal). Well-differentiated squamous cell carcinomas were always HPV-independent. HPV-independent moderately and poorly differentiated carcinomas frequently had alterations in the NOTCH signaling pathway (6/7), which were also associated with increased tumor budding (P: 0.002). HPV-associated vulvovaginal squamous cell carcinoma had PIK3CA activating mutations (7/11, 64%) as the most common genomic event, while TERT gene alterations, mainly TERT promoter mutations (14/15 cases, 93%) featured significantly in HPV-independent carcinomas. Other common abnormalities in HPV-independent tumors were TP53 mutations (13/15, 87%), CDKN2A alterations (10/15, 67%), and NOTCH1 and FAT1 mutations (7/15, 47% each). A subset of both HPV-associated and -independent tumors had NOTCH pathway alterations (6/11, 55% and 10/15, 67% respectively), but different genes in this pathway were altered in these tumors. In summary, TERT, TP53, CDKN2A, and NOTCH1 gene alterations strongly point away from an HPV-driven process (odds ratios: 0.01, 0.07, 0, and 0, respectively with p values < 0.02 for all four genes), while PIK3CA activating mutations without the other mutations strongly favors an HPV-driven tumor (odds ratio: 10.12, p value: 0.016). HPV-independent carcinomas are more likely to be moderately-poorly differentiated with intermediate to high tumor cell budding. Cancer cell fraction analysis of HPV-independent squamous carcinomas suggests that TERT and/or NOTCH1 alterations along with TP53 alterations can be the initiating event in these tumors.

Verrucous carcinoma of the vulva: Patterns of care and treatment outcomes

BACKGROUND

Verrucous vulvar carcinoma (VC) is an uncommon and distinct histologic subtype of squamous cell carcinoma (SCC). The available literature on VC is currently limited to case reports and small single institution studies.

AIMS

The goals of this study were to analyze data from the National Cancer Database (NCDB) to quantitate the incidence of VC and to investigate the effects of patient demographics, tumor characteristics, and treatment regimens on overall survival (OS) in women with verrucous vulvar carcinoma.

METHODS AND RESULTS

Patients diagnosed with vulvar SCC or VC between the years of 2004 and 2016 were identified in the NCDB. OS was assessed with Kaplan-Meier curves and the log-rank test. Construction of a Cox model compared survival after controlling for confounding variables. The reported incidence of SCC of the vulva has significantly increased since 2004 (p < .0001). In contrast, the incidence of VC has remained stable (p = .344) since 2004. Compared to SCC, VC was significantly more likely to be diagnosed in older women (p < .0001) and treated with surgery alone (p < .0001). However, on propensity score weighted analysis there was a trend toward improved 5-year OS in women with VC compared to those with SCC (63.4% vs. 57.7%, p = .0794). Multivariable Cox survival analysis showed an improvement in OS in VC patients treated with both primary site and regional lymph node surgery compared to primary site surgery alone (adjusted hazard ratio [aHR] 0.67, 95% confidence interval [CI] 0.46-0.97, p = .0357).

CONCLUSION

Verrucous carcinoma is more likely to present in older women. Regional lymph node surgery in addition to primary site surgery significantly improves OS in VC patients.

Key changes to the world health organisation (who) classification of female genital tumours introduced in the 5TH edition (2020)

An updated World Health Organisation (WHO) Classification of Female Genital Tumours was published in Autumn 2020. We discuss the major new additions and changes from the prior 2014 Classification with discussion of the reasons underlying these. A feature of the new Classification is the greater emphasis on key molecular events with integration of morphological and-molecular features. Most of the major changes from the prior Classification pertain to uterine (corpus and cervix) and vulval tumours but changes in all organs are covered.

The Vulvar Cancer Risk in Differentiated Vulvar Intraepithelial Neoplasia: A Systematic Review

Differentiated vulvar intraepithelial neoplasia (dVIN) is the precursor of human papillomavirus (HPV)-independent vulvar squamous cell carcinoma (VSCC). Given the rare incidence of dVIN, limited information on the exact cancer risk is available. We systematically reviewed the primary and recurrent VSCC risk in patients with dVIN, as well as the time to cancer development. A systematic search was performed up to July 2021 according to the PRISMA guidelines. Five reviewers independently screened articles on title, abstract and full text, followed by critical appraisal of selected articles using the Quality in Prognostic Studies (QUIPS) tool. Of the 455 screened articles, 7 were included for analysis. The absolute risk for primary VSCC in dVIN varied between 33 and 86%, with a median time to progression to VSCC of 9–23 months. The risk of developing recurrent VSCC in dVIN associated VSCC was 32–94%, with a median time to recurrence of 13–32 months. In conclusion, patients with dVIN have a high risk of developing primary and recurrent VSCC with a short time to cancer progression. Increased awareness, timely recognition, aggressive treatment and close follow-up of HPV-independent vulvar conditions including dVIN is therefore strongly recommended.

Association of HPV and EBV in Oral Verrucous Squamous Cell Carcinoma and Oral Verrucous Hyperplasia

Objective  Oral verrucous squamous cell carcinoma or oral verrucous carcinoma (OVC) is a rare verrucous variant of oral squamous cell carcinoma (OSCC), which accounts for 2 to 12% of all oral carcinomas. Oral verrucous hyperplasia (OVH) is clinically similar to OVC and has been proposed to be a precursor lesion of OVC. Etiopathogenesis of both lesions is still inconspicuous. Oncogenic viruses such as human papillomavirus (HPV) and Epstein–Barr virus (EBV) have been reported to be associated with some cases of OSCC, and we hypothesized that it may act as a causative agent of these verrucous lesions. This study aimed to investigate frequency of HPV and EBV infections in OVC and OVH.

Material and Methods  Using polymerase chain reaction (PCR), a total of 35 formalin-fixed paraffin-embedded (FFPE) tissue samples, including 27 OVC samples and 8 OVH samples, were investigated for HPV and EBV infection. HeLa and B95-8 cell lines were used as positive controls of HPV and EBV PCR, respectively.

Results  All OVC and OVH samples show a positivity to GAPDH , whereas neither HPV nor EBV PCR products was detected in both OVC and OVH samples.

Conclusions  In summary, our study demonstrated that HPV and EBV are not involved in pathogenesis of OVC and OVH. Other etiologic factors contributing to OVC and OVH need to be further clarified.

Immunohistochemistry in gynecologic carcinomas: Practical update with diagnostic and clinical considerations based on the 2020 WHO classification of tumors

This review provides an update on immunohistochemistry applications-diagnostic, prognostic, and predictive-in the pathology evaluation of gynecologic carcinomas. The 5th edition of the WHO Classification of Female Genital Tumors introduced important changes in the diagnostic classification of lower genital tract, endometrial, and ovarian carcinomas, with major influence on the routine pathology practice. Lower genital tract carcinomas and their precursor lesions are now classified based on their human papillomavirus (HPV)-associated and HPV-independent pathogenesis, reflecting the clinically significant prognostic differences and impacting the therapeutic decision-making. Immunohistochemical markers have an increasing role in the pathology evaluation of endometrial carcinomas: in addition to their traditional use in the differential diagnosis and histologic subtyping, they have also been recently advocated for prognostic classification as surrogates for the TCGA (The Cancer Genome Atlas) molecular groups. New entities - mesonephric-like adenocarcinoma and gastric (gastrointestinal)-type mucinous adenocarcinoma of the endometrium - have also been added and often require immunostains for diagnostic confirmation. Ovarian carcinomas frequently show overlapping morphologic patterns and heterogeneous appearance within the same tumor, necessitating immunohistochemical work-up. Beyond diagnostic applications, there is increasing clinical demand for screening of inherited cancer syndromes, prediction of prognosis and guiding targeted therapy. Practical issues and pitfalls related to mismatch repair protein immunohistochemistry, HER2, and PD-L1 testing are also discussed.

Clinicopathologic Diagnosis of Differentiated Vulvar Intraepithelial Neoplasia and Vulvar Aberrant Maturation

OBJECTIVE

The aim of the study was to describe the demographic, clinical, and histopathologic features of differentiated vulvar intraepithelial neoplasia (dVIN) and vulvar aberrant maturation (VAM).

METHODS

Specimens from 2010 to 2020 reported as dVIN or VAM were reviewed. Clinical data included age, rurality, symptoms, and evidence of lichen sclerosus (LS). Histopathologic data included epithelial thickness, keratinization, architectural and dyskeratotic features, stroma, p16, and p53. Differentiated vulvar intraepithelial neoplasia and VAM were distinguished by assessment of basal nuclear chromatin, enlargement, pleomorphism, and mitoses.

RESULTS

One hundred twenty women with a median age of 71 years had 179 examples of dVIN and VAM. Squamous cell carcinoma was concurrent in 66% and associated with rurality. Ten percent were asymptomatic, and all but 3 had evidence of LS. Differentiated vulvar intraepithelial neoplasia showed a range of thickness, architecture, and dyskeratosis; its unifying !feature was basal atypia. Differentiated vulvar intraepithelial neoplasia displayed hyperchromasia in 83% and easily observed mitoses in 70%. Nonkeratinizing morphology, subcategorized into basaloid and intermediate, occurred in 24% of women with dVIN. Traditional dVIN represented 62% of keratinizing cases; the remainder were atrophic (13%), hypertrophic (13%), acantholytic (8%), or subtle (5%). Vulvar aberrant maturation had abnormal stratum corneum, acanthosis, premature maturation, and enlarged vesicular nuclei. Null p53 helped distinguish dVIN from VAM and dermatoses.

CONCLUSIONS

The morphology of dVIN encompasses nonkeratinizing and keratinizing types, the latter subdivided into traditional, acantholytic, atrophic, hypertrophic, and subtle. Diagnosis relies on basal atypia with supportive p16 and p53. Atypia exists on a biologic spectrum with mild abnormalities of VAM and reactive change. Identification of dVIN and VAM requires collaboration between clinicians and pathologists experienced in vulvar disorders.

DEVIL, VAAD and vLSC constitute a spectrum of HPV-independent, p53-independent intraepithelial neoplasia of the vulva

AIMS

We aimed to characterize a large cohort of non-invasive, HPV and p53-independent verruciform lesions, such as "vulvar acanthosis with altered differentiation" (VAAD), "differentiated exophytic vulvar intraepithelial lesion" (DEVIL) and "verruciform lichen simplex chronicus" (vLSC).

METHODS AND RESULTS

We retrospectively identified from January 2008 until December 2020, 36 eligible patients with verruciform non-invasive lesions (n=36) and collected clinical, histological and follow-up parameters. Verruciform non-invasive lesions occurred at a median age of 71 years with a median follow-up of 33.5 months. Clinically, pruritus was only reported in patients with VAAD (n=3, 21%). Lesion color was significantly different across categories (p=0.028). Apart from the histopathological criteria already known to distinguish these entities (hypogranulosis, epithelial pallor and low-magnification architecture), no other significant criteria were discovered, and significant overlap was observed, particularly between VAAD and DEVIL. Patients with vLSC trended towards longer survival without recurrence compared to VAAD and DEVIL (P=0.082) yet showed comparable invasion-free survival interval (p=0.782). Squamous cell carcinomas (SCC) associated with either VAAD, DEVIL or vLSC displayed similar clinical, histopathological and biological parameters. In non-invasive precursor lesions, stromal edema was associated with invasion (p=0.015) and remained so upon Cox regression analysis (p=0.009).

CONCLUSION

Our study of HPV and p53 independent non-invasive verruciform lesions of the vulva highlights significant clinical, histopathologic and biologic overlap between VAAD, DEVIL and vLSC suggesting that these pre-invasive lesions should be viewed as a spectrum. We also show that stromal features such as edema might play an import role in progression to invasion.

Interobserver reproducibility of the diagnosis of differentiated exophytic vulvar intraepithelial lesion (DEVIL) and the distinction from its mimics

AIMS

Most vulvar squamous cell carcinomas are human papillomavirus (HPV)-associated or TP53-mutant. A third category of HPV-independent TP53-wild-type lesions is uncommon and not fully understood. Differentiated exophytic vulvar intraepithelial lesion (DEVIL) has been characterised as a precursor of this latter category. The reproducibility of the diagnosis of DEVIL and its distinction from lesions with overlapping morphology has not been studied. Our aim was to establish the interobserver agreement in the diagnosis of DEVIL and its distinction from neoplastic and reactive conditions of the vulva on haematoxylin and eosin evaluation.

METHODS AND RESULTS

A set of 35 slides was evaluated by eight reviewers (two trainees and six practising gynaecological pathologists). The set included DEVIL, condyloma, established vulvar precursors [high-grade squamous intraepithelial lesion (HSIL) and differentiated vulvar intraepithelial neoplasia (dVIN)] with superimposed acanthosis or verruciform growth, lichen simplex chronicus (LSC), and psoriasis. Kappa (κ) values were calculated. Overall, interobserver agreement was moderate (κ = 0.56), improving to substantial (κ = 0.7) when evaluation was performed by practising pathologists. Agreement was strong for the diagnosis of HSIL (κ = 0.88), and substantial for the diagnosis of DEVIL (κ = 0.61), condyloma (κ = 0.79), and LSC (κ = 0.72). Agreement was moderate for the diagnosis of dVIN (κ = 0.59) and psoriasis (κ = 0.53). Perfect agreement (6/6) among practising pathologists was observed in 43% of cases, and majority agreement (5/6 or 4/6) was observed in 48% of cases.

CONCLUSIONS

Reproducibility in the diagnosis of verruciform vulvar lesions, including the novel DEVIL, is acceptable overall. Reproducibility is higher for well-known lesions such as HSIL and condyloma than for more challenging diagnoses such as DEVIL, dVIN, and psoriasis. Agreement is higher among practising gynaecological pathologists, suggesting that training and experience improve reproducibility. Our findings support the inclusion of DEVIL as a diagnostic entity in the classification of vulvar squamous lesions.

Targeted Molecular Sequencing of Recurrent and Multifocal Non-HPV-associated Squamous Cell Carcinoma of the Vulva

Recurrent vulvar squamous cell carcinomas (SCCs) are a poorly understood and aggressive group of treatment-resistant neoplasms. Currently, it remains unclear whether these are in fact recurrences of the same primary tumor, or the development of entirely new tumors. Here, to address this question, we examined the mutational profile of a series of patients with recurrent or multifocal non-human papilloma virus (HPV)-associated vulvar SCC. We performed a targeted 33-gene next-generation sequencing panel on a series of 14 patients with recurrent or multifocal non-HPV-associated vulvar SCC and precursor neoplasms. This amounted to 54 cases (33 SCC, 1 verrucous carcinoma, 13 differentiated vulvar intraepithelial neoplasia, and 7 differentiated exophytic vulvar intraepithelial lesion), with 79 mutations detected altogether. TP53 [51/79 (65%)] was the most frequently mutated gene. Mutations in PIK3CA [16/79 (20%)), HRAS [6/79 (8%)], PTEN [4/79 (5%)], EGFR [1/79 (1%)], and GNAS [1/79 (1%)] were occasionally seen. Most patients with SCC [5/9 (56%)] recurrent, 4/5 (80%) multifocal] demonstrated a clonal relationship, and harbored the same mutations in the same genes in metachronous or synchronous tumors. A subset of the recurrent tumors [2/5 (40%)] recurred with additional mutations. These clonal relationships were shared between SCC and differentiated vulvar intraepithelial neoplasia in each case. By contrast, a small number of recurrent tumors [3/9 (33%)] demonstrated novel mutations, entirely different from the primary tumor. Thus, our findings suggest that recurrent non-HPV-associated vulvar SCC can arise from 2 mechanisms.

Molecular Landscape of Vulvar Squamous Cell Carcinoma

Vulvar squamous cell carcinoma (VSCC) is a rare malignancy with dual pathogenesis, Human papillomavirus (HPV)-associated and HPV-independent, with a poorly explored molecular landscape. We aimed to summarize the findings of the series analyzing molecular hallmarks of this neoplasm. In January 2021, we conducted a comprehensive literature search using Pubmed Medline and Scopus to identify publications focused on genomic profiling of VSCC. Observational studies, including both prospective and retrospective designs, evaluating molecular alterations in VSCC were deemed eligible. A total of 14 studies analyzing 749 VSCC were identified. The study series were heterogeneous in HPV testing and sequencing strategies, included small sets of tumors and cancer genes, and commonly lacked survival analysis. Only one extensive targeted next-generation sequencing-based study comprised a large cohort of 280 VSCC. The mutated genes, their number, and frequencies were highly variable between the series. Overall, TP53 and CDKN2A, followed by PIK3CA, HRAS, and PTEN, were the most frequently studied and mutated genes. Mutations involved in the PI3K/AKT/mTOR pathway, including TP53, HRAS, KRAS, and PIK3CA, have been consistently reported across the studies. However, the role of individual mutations or pathways in the development of VSCC remains unclear. In conclusion, heterogeneity and the small sample size of available molecular series contribute to a limited view of the molecular landscape of VSCC. Large-scale genome- or exome-wide studies with robust HPV testing are necessary to improve the molecular characterization of VSCC.

[Vulvar intraepithelial neoplasias]

Vulvar squamous cell carcinoma arises from precursor lesions: vulvar intraepithelial neoplasias (VIN). Most of them are caused by the human papillomavirus (HPV), and the precursor lesion for this group is VIN usual type/high grade squamous intraepithelial lesion (uVIN/HSIL) of variable clinical presentation and having a light invasive potential. Some VIN are HPV-independent and arise in older women against the background of chronic dermatoses, mostly lichen sclerosus. Their histological diagnosis is more subtle. They have a higher invasive potential. A third precursor, leading to well-differentiated, or even verrucous, carcinomas, is still ill-defined to this day. We detail these lesions' clinics, histology, and biomarkers (immunohistochemical and molecular).

Molecular characterization of invasive and in situ squamous neoplasia of the vulva and implications for morphologic diagnosis and outcome

Human papillomavirus (HPV)-independent vulvar squamous cell carcinoma (VSCC) is an aggressive clinical entity. Current diagnostic guidelines for premalignant lesions are ambiguous, and their molecular profile and progression events are still unclear. We selected 75 samples, from 40 patients, including 33 VSCC, 8 verrucous carcinomas (VC), 13 differentiated-type vulvar intraepithelial neoplasia (dVIN), 11 suspicious for dVIN (?dVIN), 6 differentiated exophytic vulvar intraepithelial lesions (DE-VIL), 2 vulvar acanthosis with altered differentiation (VAAD), and 2 usual-type vulvar intraepithelial neoplasia (uVIN/HSIL). Invasive and precursor lesions were matched in 29 cases. Clinical information, p16 immunohistochemistry, and mutation analysis were performed on all lesions. All dVIN, ?dVIN, DE-VIL, and VAAD were p16 negative, all uVIN/HSIL were p16 positive. In the HPV-independent group, mutations were identified in 6 genes: TP53 (n = 40), PIK3CA (n = 20), HRAS (n = 12), MET (n = 5), PTEN (n = 4), and BRAF (n = 1). TP53 mutations occurred in 73% (22/30) VSCC, 85% (11/13) dVIN, 70% (7/10) ?dVIN and no VC (0/8), DE-VIL (0/6) nor VAAD (0/2). Basal atypia was the only reliable feature of TP53 mutations. ?dVIN lesions that were non-acanthotic and atypical but obscured by inflammation, all harbored TP53 mutations. In lesions without TP53 mutations, PIK3CA (50% VC, 33% DE-VIL, 100% VAAD, 40% VSCC) and HRAS (63% VC, 33% DE-VIL, 0% VAAD, 20% VSCC) mutations were found. Mutational progression from in situ to invasive was seen (7/26, 27%) and usually involved TP53 (4/26, 15%). Cases with TP53 and PIK3CA co-mutations had the worse clinical outcomes (p < 0.001). We recommend testing for p53 in all HPV-independent lesions suspicious for dVIN, even in the presence of marked inflammation or non-acanthotic skin, particularly when close to a margin. VC, VAAD, and DE-VIL, were almost never mutated for TP53, but instead often harbored PIK3CA and HRAS mutations. In VSCC, combined TP53 and PIK3CA mutations may inform prognosis.

Diagnostic Criteria for Differentiated Vulvar Intraepithelial Neoplasia and Vulvar Aberrant Maturation

OBJECTIVE

The aim of the study was to describe the features required for diagnosis of differentiated vulvar intraepithelial neoplasia (dVIN) and vulvar aberrant maturation (VAM).

MATERIALS AND METHODS

The International Society of the Study of Vulvovaginal Diseases tasked the difficult pathologic diagnoses committee to develop consensus recommendations for clinicopathologic diagnosis of vulvar lichen planus, lichen sclerosus, and dVIN. The dVIN subgroup reviewed the literature and formulated diagnostic criteria that were reviewed by the committee and then approved by the International Society of the Study of Vulvovaginal Diseases membership.

RESULTS

Differentiated vulvar intraepithelial neoplasia is the immediate precursor of human papillomavirus (HPV)-independent vulvar squamous cell carcinoma and shows a spectrum of clinical and microscopic appearances, some overlapping with HPV-related neoplasia. The histopathologic definition of dVIN is basal atypia combined with negative or nonblock-positive p16 and basal overexpressed, aberrant negative, or wild-type p53. The most common pattern of dVIN is keratinizing with acanthosis, aberrant rete ridge pattern, and premature maturation. The morphologic spectrum of keratinizing dVIN includes hypertrophic, atrophic, acantholytic, and subtle forms. A few dVIN cases are nonkeratinizing, with basaloid cells replacing more than 60% of epithelium. Vulvar aberrant maturation is an umbrella term for lesions with aberrant maturation that arise out of lichenoid dermatitis and lack the basal atypia required for dVIN.

CONCLUSIONS

Evaluation of women at risk for dVIN and VAM requires a collaborative approach by clinicians and pathologists experienced in vulvar disorders. Close surveillance of women with lichen sclerosus and use of these recommendations may assist in prevention of HPV-independent squamous cell carcinoma through detection and treatment of dVIN and VAM.

HPV-independent Precursors Mimicking High-grade Squamous Intraepithelial Lesions (HSIL) of the Vulva

Two etiopathogenic types of vulvar squamous cell carcinoma (VSCC) have been described: human papillomavirus (HPV)-associated and HPV-independent. Precursor lesions, frequently identified in the adjacent skin, are also distinct in the 2 types of VSCC: high-grade squamous intraepithelial lesions (HSILs) in HPV-associated VSCC and differentiated vulvar intraepithelial neoplasia (dVIN) or vulvar acanthosis with altered differentiation in HPV-independent VSCC. Although HPV-independent precursors mimicking HSIL have been described in the vulva, their frequency and morphologic spectrum have not been completely characterized. We explored, in a large series of HPV-independent VSSC, the frequency and the histologic features of precursors mimicking HSIL. We included 779 DNA HPV-negative/p16-negative VSCC with at least 1 cm of adjacent skin. We evaluated the histologic and immunohistochemical (p16 and p53) characteristics of the intraepithelial lesions, focusing on precursors mimicking HPV-associated vulvar HSIL. A total of 254 tumors (33%) had adjacent premalignant lesions. Of them, 186 (73%) had dVIN, 22 (9%) had vulvar acanthosis with altered differentiation, and 46 (18%) had lesions that mimicked HSIL. The mean age of the patients with these HSIL-like lesions was 72±15 years. Twenty-six of these HSIL-like lesions had basaloid morphology, 13 warty, and 7 mixed basaloid/warty features. All the HSIL-like precursors were DNA HPV-negative/p16-negative; 74% of them showed p53 abnormal staining and 35% of them had areas of conventional dVIN. In conclusion, about one fifth of the HPV-independent precursors mimic HSIL, showing either basaloid or warty features. Older age and the presence of areas of typical HPV-independent intraepithelial lesions, together with p16 negativity, should raise suspicion of an HPV-independent etiology.

p53 Immunohistochemical Patterns in HPV-Independent Squamous Cell Carcinomas of the Vulva and the Associated Skin Lesions: A Study of 779 Cases

Human papillomavirus (HPV)-independent vulvar squamous cell carcinomas (VSCC) and its precursors frequently harbour TP53 mutations. Recently, six p53 immunohistochemical (IHC) patterns have been defined, which have shown strong correlation with TP53 mutation status. However, few studies have applied this new six-pattern framework and none of them exhaustively compared p53 IHC positivity and patterns between invasive VSCC and adjacent skin lesion. We performed p53 IHC in a series of 779 HPV-independent VSCC with adjacent skin and evaluated the IHC slides following the newly described classification. Some 74.1% invasive VSCC showed abnormal p53 IHC staining. A skin lesion was identified in 450 cases (57.8%), including 254 intraepithelial precursors and 196 inflammatory/reactive lesions. Two hundred and ten of 450 (47%) VSCC with associated skin lesions showed an abnormal p53 IHC stain, with an identical staining pattern between the VSCC and the adjacent skin lesion in 80% of the cases. A total of 144/450 (32%) VSCC showed wild-type p53 IHC both in the invasive VSCC and adjacent skin lesion. Finally, 96/450 (21%) VSCC showed p53 IHC abnormal staining in the invasive VSCC but a wild-type p53 staining in the skin lesion. Most of the discordant cases (70/96; 73%) showed adjacent inflammatory lesions. In conclusion, the p53 IHC staining and pattern are usually identical in the VSCC and the intraepithelial precursor.

Differentiated exophytic vulvar intraepithelial lesion: Clinicopathologic and molecular analysis documenting its relationship with verrucous carcinoma of the vulva

Verruciform proliferations of the vulva unrelated to HPV infection are rare. The term differentiated exophytic vulvar intraepithelial lesion (DEVIL) was recently proposed for these lesions, which harbor recurrent PIK3CA mutations. It is still unclear whether DEVIL is related to verrucous carcinoma, a neoplasm characterized by persistence and local recurrence but nil risk of distant spread. Specimens identified using the words "verruciform" and "verrucous" were reviewed. Diagnosis of DEVIL required verruciform acanthosis, hyper and/or parakeratosis, hypogranulosis, cytoplasmic pallor, and bland nuclei. Verrucous carcinoma required, in addition, discontinuous, bulbous, puzzle-like nests in the stroma. A targeted next-generation sequencing using a custom 11-gene panel was performed. Eighteen specimens corresponding to ten patients with DEVIL and/or verrucous carcinoma were included. Median age at presentation was 66 years for DEVIL and 70 years for verrucous carcinoma. A similar spectrum of prevalent mutations was found in both lesions involving HRAS, PIK3CA, and BRAF. DEVIL preceded verrucous carcinoma and/or was diagnosed concurrently or in subsequent follow-up in five patients. In four of these, the same mutation was identified in DEVIL and synchronous or metachronous carcinoma. All cases showed wild-type 53 staining and lacked pathogenic TP53 mutations. DEVIL is a rare form of squamous proliferation characterized by prevalent PIK3CA and HRAS mutations. Its temporal relationship with verrucous carcinoma and their shared mutational profile in some patients suggest that DEVIL is a precursor of verrucous carcinoma. Moreover, given their morphologic and molecular overlap and the nil risk of verrucous carcinoma for distant spread, it is conceivable that DEVIL and verrucous carcinoma represent a spectrum of the same entity.

Putative precancerous lesions of vulvar squamous cell carcinoma

Precursor lesions of vulvar squamous cell carcinoma (VSCC) can be divided into two major biologic and prognostic groups: HPV-associated and HPV-independent VSCC. These two pathways are categorized as usual vulvar intraepithelial neoplasia (uVIN) with progression to basaloid or warty VSCC and differentiated vulvar intraepithelial neoplasia (dVIN) with progression to the more common keratinizing VSCC. While the HPV-dependent pathway to squamous cell carcinoma is well-understood, the development of squamous cell carcinoma from HPV-independent lesions is less clear. The majority of HPV-independent lesions fall into the dVIN category, and mutations in TP53 have been implicated as the driver behind their development. Other less common HPV-independent precursor lesions, termed differentiated exophytic vulvar intraepithelial lesion (DEVIL) and vulvar acanthosis with altered differentiation (VAAD), have also been characterized as precursors to keratinizing and verrucous VSCC. Inflammatory conditions of the vulva such as lichen sclerosus and lichen simplex chronicus also put patients at risk for developing VSCC. We herein evaluate the available evidence and biologic basis for these VSCC precursor lesions, among other speculated entities, and discuss their clinical, diagnostic, and prognostic features.

Vulval squamous cell carcinoma and its precursors

Vulval squamous cell carcinoma (VSCC) can arise through two distinct pathways [human papillomavirus (HPV)-associated and HPV-independent], and these VSCC variants are recognised as different disease entities on the basis of different aetiologies, morphological features, molecular events during oncogenesis, precursor lesions, prognosis, and response to treatment. The precursor of HPV-associated VSCC, variously referred to as high-grade squamous intraepithelial lesion (HSIL) [vulvar intraepithelial neoplasia (VIN) 2/3] or usual-type VIN, is morphologically identical to the more common HSIL (cervical intraepithelial neoplasia 2/3) of the cervix. The precursor lesions of HPV-independent VSCC include differentiated VIN, differentiated exophytic vulvar intraepithelial lesion, and vulvar acanthosis with altered differentiation; these have been under-recognised by pathologists in the past, leading to delays in treatment. This review will discuss the recent advances in diagnostic surgical pathology of VSCC and its precursors, and how these diagnoses can impact on patient management.

Major p53 immunohistochemical patterns in in situ and invasive squamous cell carcinomas of the vulva and correlation with TP53 mutation status

The recent literature has shown that vulvar squamous cell carcinoma (VSCC) can be stratified into two prognostically relevant groups based on human papillomavirus (HPV) status. The prognostic value of p53 for further sub-stratification, particularly in the HPV-independent group, has not been agreed upon. This disagreement is likely due to tremendous variations in p53 immunohistochemical (IHC) interpretation. To address this problem, we sought to compare p53 IHC patterns with TP53 mutation status. We studied 61 VSCC (48 conventional VSCC, 2 VSCC with sarcomatoid features, and 11 verrucous carcinomas) and 42 in situ lesions (30 differentiated vulvar intraepithelial neoplasia [dVIN], 9 differentiated exophytic vulvar intraepithelial lesions [deVIL], and 3 high-grade squamous intraepithelial lesions or usual vulvar intraepithelial neoplasia [HSIL/uVIN]). IHC for p16 and p53, and sequencing of TP53 exons 4-9 were performed. HPV in situ hybridization (ISH) was performed in selected cases. We identified six major p53 IHC patterns, two wild-type patterns: (1) scattered, (2) mid-epithelial expression (with basal sparing), and four mutant patterns: (3) basal overexpression, (4) parabasal/diffuse overexpression, (5) absent, and (6) cytoplasmic expression. These IHC patterns were consistent with TP53 mutation status in 58/61 (95%) VSCC and 39/42 (93%) in situ lesions. Cases that exhibited strong scattered staining and those with a weak basal overexpression pattern could be easily confused. The mid-epithelial pattern was exclusively observed in p16-positive lesions; the basal and parabasal layers that had absent p53 staining, appeared to correlate with the cells that were positive for HPV-ISH. This study describes a pattern-based p53 IHC interpretation framework, which can be utilized as a surrogate marker for TP53 mutational status in both VSCC and vulvar in situ lesions.

British Gynaecological Cancer Society (BGCS) vulval cancer guidelines: Recommendations for practice

The purpose of this guideline is to collate evidence and propose evidence-based guidelines for the diagnosis and management of adult patients with vulva carcinoma treated in the UK. Malignant melanoma may present via similar routes and will be discussed. The reader is referred to the Ano-uro-genital Mucosal Melanoma Full Guideline [1] for more detailed recommendations. The management of vulval sarcoma is outside of the scope of this guideline. For further information, including details of guideline development and GRADE of recommendations, please see BGCS website for details (https://www.bgcs.org.uk/professionals/guidelines-for-recent-publications/).

Clinicopathologic features of Buschke-Löwenstein tumor: a multi-institutional analysis of 38 cases

Buschke-Löwenstein tumor (BLT) is a rare sexually transmitted disease, mostly described in clinical literature as case reports or small series. Here, we investigated the clinicopathologic features of BLT in a total of 38 cases retrieved from multiple academic institutions. The average age was 47.6 ± 12.8 (mean ± SD) years old at diagnosis. The male to female ratio was 4.4:1. Common presenting symptoms were pain/discomfort, bleeding, mass lesion, and discharge. It was frequently linked to smoking and positive human immunodeficiency virus status. The tumor size and thickness were 8.5 ± 6.6 cm and 1.5 ± 1.3 cm, respectively. Histologically, 19 (50%) cases had an invasive squamous cell carcinoma component and were associated with high-risk human papillomavirus infection. There was no lymphovascular or perineural invasion, or nodal metastasis at initial diagnosis. BLTs with invasion had higher frequency of dyskeratosis, neutrophilic microabscesses, and abnormal mitoses, but lower frequency of pushing border compared with BLTs without invasion. All patients underwent wide excision, and some also received chemoradiation therapy. After a median follow-up of 23 months (range 1-207), the recurrence rate was 23.7% and disease-specific mortality was 2.6%. In summary, we presented the largest case series of BLT to date to characterize its unique clinicopathologic features. Our study indicated that certain histologic features such as dyskeratosis, neutrophilic microabscess, and abnormal mitosis in the non-invasive portion may be important clues on lesional biopsy to predict the presence of underlying invasive carcinoma.

Precursor lesions of vulvar squamous cell carcinoma - histology and biomarkers: A systematic review

The precursor lesion of vulvar squamous cell carcinoma (VSCC), namely vulvar intraepithelial neoplasia (VIN), is classified as: human papillomavirus (HPV)-related high grade squamous intraepithelial lesion (HSIL), and HPV-independent differentiated VIN (dVIN). Traditionally, histology and immunohistochemistry (IHC) have been the basis of diagnosis and classification of VIN. HSIL shows conspicuous histological atypia, and positivity on p16-IHC, whereas dVIN shows less obvious histological atypia, and overexpression or null-pattern on p53-IHC. For both types of VIN, other diagnostic immunohistochemical markers have also been evaluated. Molecular characterization of VIN has been attempted in few recent studies, and novel genotypic subtypes of HPV-independent VSCC and VIN have been identified. This systematic review appraises the VSCC precursors identified so far, focusing on histology and biomarkers (immunohistochemical and molecular). To gain further insights into the carcinogenesis and to identify additional potential biomarkers, gene expression omnibus (GEO) datasets on VSCC were analyzed; the results are presented.

Vulvamalignome: eine interdisziplinäre Betrachtung

Vulvamalignome stellen die vierthäufigste Gruppe von gynäkologischen Krebserkrankungen dar. Erste Ansprechpartner sind typischerweise niedergelassene Dermatologen und Gynäkologen. Mit der jeweiligen Fachexpertise findet die Diagnose und Therapie idealerweise interdisziplinär zwischen spezialisierten Dermatoonkologen und gynäkologischen Onkologen statt. Vulvamalignome sind überwiegend Erkrankungen des höheren Lebensalters, obwohl alle histologischen Subtypen auch bei Frauen unter 30 Jahren vorkommen. Die Diagnose erfolgt oft verzögert. Eine genaue Kartierung von Biopsien (Mapping) ist von großer Bedeutung, da Lokalisation und Entfernung von der Mittellinie in Abhängigkeit von der zugrunde liegenden Histologie das operative Vorgehen bestimmen. Plattenepithelkarzinome machen mehr als 76 % der Vulvamalignome aus und vulväre intraepitheliale Neoplasien (VIN) sind dabei wichtige Vorstufen. Der zweithäufigste Typ der Vulvakarzinome ist das Basalzellkarzinom. Melanome machen 5,7 % der vulvären Malignome aus und ihre Prognose ist schlechter als die der kutanen Melanome. Die meisten Studien zu Checkpoint-Inhibitoren und zielgerichteten Therapien haben Patientinnen mit vulvären Melanomen nicht ausgeschlossen. Die vorliegende Evidenz wird im folgenden diskutiert. Die Methode der Wahl bei lokal resezierbaren Vulvamalignomen ist die Exzision. Angesichts ihrer Seltenheit sollte die Behandlung in spezialisierten Zentren erfolgen, um eine optimale Krankheitskontrolle zu erreichen und Kontinenz und sexuelle Funktion bestmöglich zu erhalten.

Vulvar malignancies: an interdisciplinary perspective

Vulvar cancer represents the fourth most common gynecologic malignancy and is often encountered by the general Dermatologist or Gynecologist. Dermatooncologists and Gynecologic Oncologists share expertise in this field and the diagnosis and treatment should ideally be interdisciplinary. All subtypes are typically seen in the later decades of life, although all histologic subtypes have been described in women younger than 30 years. The diagnosis is often delayed. Exact mapping of biopsies is of high importance, as the location and distance from the midline guides the surgical approach depending on the underlying histology. Squamous cell carcinoma accounts for more than 76 % of vulvar cancer with vulvar intraepithelial neoplasia being an important precursor. Basal cell carcinoma is the second most common vulvar malignancy. Melanoma accounts for 5.7 % of vulvar cancer and has a worse prognosis compared to cutaneous melanoma. Most of the trials on checkpoint inhibitors and targeted therapy have not excluded patients with vulvar melanoma and the preliminary evidence is reviewed in the manuscript.

Surgery remains the primary treatment modality of locally resectable vulvar cancer. In view of the rarity, the procedure should be performed in dedicated cancer centers to achieve optimal disease control and maintain continence and sexual function whenever possible.

New Directions in Vulvar Cancer Pathology

PURPOSE OF REVIEW

The aim of this article is to provide clinicians and pathologists with an understanding of the aetiopathology, pathogenesis and classification of vulval neoplasia and their molecular correlates.

RECENT FINDINGS

There is an increased understanding of subcellular changes in vulvar malignancies. These provide the direction for further research and aid personalised treatment for patients. The article explores concepts of the aetiology of vulvar cancer and updates the reader with the equivalence of terminology of preneoplastic vulval disease. The differential diagnosis of squamous neoplasia and their clinicopathological correlation is detailed. The salient findings from recent literature into the understanding of the disease of squamous cell neoplasia and rare vulvar malignancies are summarised.

Human Papillomavirus-Independent Squamous Lesions of the Vulva

The pathogenesis of vulvar squamous neoplasia has 2 pathways: human papillomavirus (HPV)-dependent and HPV-independent. The HPV-dependent pathway in the vulva follows the same progression as HPV-dependent lesions elsewhere in the gynecologic tract-HPV infection results in high-grade squamous intraepithelial lesion with subsequent progression to basaloid squamous cell carcinoma. The HPV-independent pathway is more complex, with a variety of precursor lesions and molecular alterations. Although the most recognized form of HPV-independent vulvar lesion is differentiated vulvar intraepithelial neoplasia, recent explorations have elucidated new precursors. This review provides an update on HPV-independent risk factors and precursor lesions for squamous cell carcinoma of the vulva.

Clinical and molecular classification of vulvar squamous pre-cancers

Vulvar intraepithelial neoplasia (VIN) is a precursor to vulvar squamous cell carcinoma and is defined histopathologically by the presence of atypia. VIN has been classified into two types: usual vulvar intraepithelial neoplasia (uVIN), which is also referred to as a vulvar high-grade squamous intra-epithelial lesion (HSIL), and differentiated VIN (dVIN). The former is associated with chronic infection by sub-types of the human papilloma virus (HPV), whereas dVIN is HPV-independent and frequently associated with lichen sclerosus. The distinction is important because dVIN has a greater risk of, and more rapid transit to, vulvar squamous cell carcinoma. Furthermore, dVIN-associated vulvar cancers have an increased risk of recurrence and higher mortality than those arising from HSIL. Molecular characterization of vulvar squamous cell carcinoma precursors using next-generation sequencing is a relatively novel, but rapidly advancing field. This review appraises recent studies that have investigated the risks of progression to vulvar malignancy associated with HSIL and dVIN, the prognosis of HPV-dependent and HPV-independent vulvar squamous cell carcinomas, and conducted next generation sequencing mutation analyses to elucidate the genomic profiles underlying VIN. These studies suggest that HSIL and dVIN are characterized by different underlying molecular alterations that may have important implications for treatment and follow-up of women diagnosed with vulvar squamous cell cancer.

Verrucous Carcinoma of the Vulva: A Case Report and Literature Review

Patient: Female, 50

Final Diagnosis: Verrucous carcinoma of the vulva

Symptoms: Itch • tumor

Medication: —

Clinical Procedure: Surgery

Specialty: Surgery