Differentiated Intraepithelial Neoplasia of the Vulva:

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.

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.

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.

Comparison of p53 immunohistochemical staining in differentiated vulvar intraepithelial neoplasia (dVIN) with that in inflammatory dermatoses and benign squamous lesions in the vulva

AIMS

Differentiated vulvar intraepithelial neoplasia (dVIN), the precursor lesion to human papillomavirus-independent vulvar squamous cell carcinoma (VSCC), can be difficult to distinguish from vulvar inflammatory dermatoses. Our goal was to determine if p53 could be a useful biomarker for dVIN, by characterizing p53 percentage, intensity and patterns of staining in dVIN and its histological mimics.

METHODS AND RESULTS

We studied p53 immunohistochemical staining patterns in 16 dVIN cases and 46 vulvar non-neoplastic squamous lesions [12 lichen sclerosus (LS); seven lichen simplex chronicus; three lichen planus (LP); six psoriasis; 13 spongiotic dermatitis (SPO); and five candidiasis]. dVIN cases were adjacent to a p16-negative invasive VSCC in resection specimens. All dVIN cases showed null-type or moderate to strong uniform p53 staining in >70% of basal cells, with moderate to strong continuous parabasal staining extending to two-thirds of the epidermis. This was in contrast to weak or weak to moderate patchy p53 staining in the majority of other lesions. Moderate to strong and increased basal p53 staining (≥70%) was also observed in a subset of LS cases (5/12, 42%), LP cases (1/3, 33%), and SPO cases (36%, 4/11); however, in all categories, this was limited to the basal layer, and any staining in the parabasal layers was patchy.

CONCLUSION

Strong and uniform p53 staining of basal cells, extending into the parabasal layers, and a complete absence of staining (null type) is useful in distinguishing dVIN from other mimics in the vulva. p53 staining of lesser intensity or quantity, particularly basal overexpression only, overlaps with that in vulvar inflammatory lesions.

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.

Vulvar intraepithelial neoplasia: Incidence and long-term risk of vulvar squamous cell carcinoma

The risk of vulvar squamous cell carcinoma (VSCC) in patients with high-grade vulvar intraepithelial neoplasia (VIN) is considered lower in high-grade squamous intraepithelial lesion (HSIL) compared to differentiated VIN (dVIN), but studies are limited. Our study investigated both the incidence of high-grade VIN and the cumulative incidence of VSCC in patients with HSIL and dVIN separately. A database of women diagnosed with high-grade VIN between 1991 and 2011 was constructed with data from the Dutch Pathology Registry (PALGA). The European standardized incidence rate (ESR) and VSCC risk were calculated, stratified for HSIL and dVIN. The effects of type of VIN (HSIL vs dVIN), age and lichen sclerosis (LS) were estimated by Cox regression. In total, 1148 patients were diagnosed with high-grade VIN between 1991 and 2011. Between 1991-1995 and 2006-2011, the ESR of HSIL increased from 2.39 (per 100 000 woman-years) to 3.26 and the ESR of dVIN increased from 0.02 to 0.08. The 10-year cumulative VSCC risk was 10.3%; 9.7% for HSIL and 50.0% for dVIN (log rank P < .001). Type of VIN, age and presence of LS were independent risk factors for progression to VSCC, with hazard ratios of 3.0 (95% confidence interval [CI] 1.3-7.1), 2.3 (95% CI 1.5-3.4) and 3.1 (95% CI 1.8-5.3), respectively. The incidence of high-grade VIN is rising. Because of the high cancer risk in patients with dVIN, better identification and timely recognition are urgently needed.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Laryngeal Squamous Cell Carcinomas are Commonly Associated With Differentiated Squamous Intraepithelial Neoplasia With or Without an Admixture With Usual Type of Squamous Intraepithelial Neoplasia: Clinical and Pathologic Significance

BACKGROUND

Differentiated squamous intraepithelial neoplasia (dSIN) is a pathway in the development of invasive squamous cell carcinoma (SCC) distinct from the usual-type squamous intraepithelial neoplasia (uSIN) and has not been described in the larynx.

MATERIALS AND METHODS

Sixty-nine consecutive cases of SCC were identified which included 25 dSIN, 13 uSIN, and 31 mixed dSIN+usual-like SIN (u-like SIN) cases.

RESULTS

dSIN was characterized by atypical squamous cells limited to the basal/parabasal layers and u-like SIN was characterized by cytologic atypia limited to less than full thickness. Despite the lack of neoplastic involvement of the full thickness of the epithelium, these types of SIN were commonly connected with invasive carcinoma. Prior biopsies demonstrating only dSIN, without the underlying invasive SCC, were underdiagnosed in 2 cases. Because of the frequent keratinization, u-like SIN likely represents the "keratinized dysplasia" and shows changes suggestive of dSIN with upward spread of neoplastic cells into the upper layer of the epithelium.

CONCLUSIONS

Laryngeal dSIN represents an important but under recognized pathway of invasive SCC development. As moderate dysplasia of uSIN type are not associated with invasive SCC, labeling u-like SIN as dysplasia of grade 2 or 3 likely leads to the controversies in the current grading systems in the upper aerodigestive system and causes confusion for clinicians.

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.

Classic Vulvar Intraepithelial Neoplasia With Superimposed Lichen Simplex Chronicus: A Unique Variant Mimicking Differentiated Vulvar Intraepithelial Neoplasia

High-grade vulvar intraepithelial neoplasia, a precursor lesion to vulvar squamous cell carcinoma, is subdivided into 2 types, classic or usual vulvar intraepithelial neoplasia (CVIN) and differentiated vulvar intraepithelial neoplasia (DVIN). CVIN, which is a human papilloma virus (HPV)-dependent lesion, is typically distinguished from DVIN, a p53 mutation-dependent process, by its distinct histomorphologic and immunohistochemical characteristics. However, distinguishing between the 2 entities becomes challenging in cases of CVIN with superimposed inflammatory changes, especially lichen simplex chronicus (LSC). Twelve cases of DVIN, 9 cases of LSC, and 9 cases of CVIN with superimposed LSC were assessed for a number of morphologic features, including hyperkeratosis, hypergranulosis, acanthosis, hypercellularity, abnormal maturation (i.e. abnormal keratinization close to the base and/or dyskeratosis), hyperchromasia, and basal atypia. Immunohistochemistry for p53, p16, and MIB-1 was performed for all cases. When sufficient tissue was available, HPV genotyping was performed for cases of CVIN with superimposed LSC. DVIN uniformly demonstrated abnormal maturation, and atypia involving the basal cell layer; they were all p16 negative and demonstrated p53 positivity of moderate to strong intensity in a basal and parabasal distribution. CVIN with superimposed LSC frequently displayed hyperchromasia involving the basal 3 to 4 cell layers, basal to full-thickness atypia, and apoptosis. CVIN with superimposed LSC demonstrated intense p16 positivity extending from the basal cells to the mid-epithelium and a reduction or loss of staining in maturing keratinocytes. P53 staining revealed a unique pattern of parabasal and mid-epithelial weak to moderate staining with sparing of the basal layer. Cases of LSC demonstrated heterogenous p53 positivity and were negative for p16. MIB-1 staining showed a similar range of positivity for all diagnoses. HPV genotyping revealed HPV 16 in all 5 cases of CVIN with LSC that underwent testing. We conclude that, although CVIN with superimposed LSC can closely resemble DVIN, morphologic features such as nuclear hyperchromasia uniformly involving the basal 3 to 4 cell layers, apoptosis, and absent or less pronounced cytoplasmic maturation are more suggestive of CVIN with superimposed LSC. In cases where the morphology remains ambiguous, immunohistochemistry for both p16 and p53 can be helpful. In particular, p53 parabasal and mid-epithelial staining without involvement of the basal layer appears to be a characteristic finding in CVIN with superimposed LSC. MIB-1 staining is of little utility in distinguishing between these entities and should not be routinely performed.

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.

Human papillomavirus and nonhuman papillomavirus pathways to vulvar squamous cell carcinoma: A review

Vulvar squamous cell carcinoma (VSCC) is a rare tumor of the female genital tract. While previously considered a disease of older women, the epidemiologic landscape is changing with more young women diagnosed with VSCC and its precursor lesions. This may be secondary to the global increase in human papillomavirus (HPV) infection of the lower genital tract. While VSCC precursor lesions have been described for many years, the terminology, and thus the understanding and reproducibility of these lesions have been debated. In the most recent publication from the International Society of the Study of Vulvovaginal Disease (ISSVD), there is a distinction between high-risk vulvar lesions associated with HPV infection (vulvar HSIL) and high-risk vulvar lesions that are not thought to be associated with HPV infection (differentiated VIN or dVIN). These precursors have different risk factors and thus affect different populations, leading to two separate pathways for developing VSCC. The HPV-related VSCC is likely to have a better prognosis than the non-HPV-related VSCC, as seen in other disease sites. Early-stage VSCC may be surgically treated with margin and node status affecting whether adjuvant radiation is recommended. Advanced stage VSCC may be unresectable, requiring neoadjuvant chemoradiation. Although VSCC is a rare disease, ongoing studies investigating the different pathways leading to carcinogenesis may increase the understanding of VSCC and improve therapeutic options for patients.

Assessment of CK17 as a Marker for the Diagnosis of Differentiated Vulvar Intraepithelial Neoplasia

Differentiated vulvar intraepithelial neoplasia (dVIN), precursor of vulvar squamous cell carcinoma, is human papilloma virus independent and often found in a background of lichen sclerosus (LS) and lichen simplex chronicus (LSC). Subtle histologic findings make the diagnosis of dVIN difficult, and, although the use of p53 and Ki-67 has been of some value, there is a need for a better immunohistochemical marker. Cytokeratin 17 (CK17), a cytoskeletal intermediate filament protein, has previously been used in the diagnosis of anogenital lesions. Here we evaluated CK17 in dVIN in comparison with LS, LSC, and usual VIN (uVIN/HSIL). Twenty-nine cases of dVIN, 9 cases of uVIN, 8 cases of LS, and 7 of LSC were evaluated using CK17, Ki-67, and p53. All 29 dVIN cases displayed immunoreactivity for CK17, with 27 (93%) showing intermediate to strong and diffuse reactivity. No cases of uVIN displayed diffuse CK17 expression, whereas 63% of LS and 29% of LSC displayed intermediate to strong diffuse immunoreactivity, confined to the upper half of the epithelium. P53 and Ki-67 expression was present in varying degrees in all types of lesions, displaying limited discriminatory power for dVIN. Our findings suggest that CK17, although not specific for dVIN, when combined with histologic findings, Ki-67, and p53 immunohistochemistry, can be a marker of vulvar dysplasia and serve as an adjunct in the diagnosis of dVIN. Specifically, in small biopsies, the presence of diffuse suprabasal or full thickness expression strongly favors a diagnosis of dVIN over LSC, whereas focal and/or superficial expression supports a diagnosis of LSC.

Differentiated cervical intraepithelial neoplasia-associated invasive cervical squamous cell carcinoma as a source of major cytopathological and surgical pathological discrepancy in Papanicolaou smear screening tests

INTRODUCTION

Differentiated cervical intraepithelial neoplasia (dCIN) analogous to differentiated squamous intraepithelial neoplasia of the vulva is characterised by the proliferation of atypical cells limited to the basal/parabasal layers. Exfoliative cytology of dCIN has not been investigated.

METHODS AND RESULTS

A 46-year-old woman, with a history of normal Papanicolaou (Pap) smear up to 2 years prior to the occurrence of postcoital vaginal bleeding had two consecutive Pap smears, which only revealed atypical squamous cells of unknown significance (ASCUS). The subsequent cervical biopsy revealed dCIN. The cone biopsy showed the invasive cervical squamous cell carcinoma (ICC) that developed from the overlying dCIN. Review of 32 consecutive cases of ICC revealed a second case of dCIN-associated ICC (Group 1) preceded by ASCUS suspicious for high-grade neoplastic cells. In both cases, the ASCUS were keratinised atypical cells without koilocytosis. In addition, there were another seven cases showing focal dCIN associated with extensive usual CIN (Group 2). In comparison with the remaining 24 cases with usual CIN (Group 3), Group 2 lesions occurred in younger patients (mean ages of 36 ± 3 vs 47 ± 9 years) and were associated with shorter intervals after the last normal Pap smears. Pap smears in Group 2 occasionally consisted only of ASCUS cells.

CONCLUSIONS

dCIN may occur in the cervix and accounts for a short interval of normal Pap smears and false negative or low-grade Pap smears in ICC.

Vulvar cancer: Two pathways with different localization and prognosis

BACKGROUND

Two etiologic pathways for vulvar squamous cell carcinoma (SCC) are described: in a background of lichen sclerosus and/or differentiated vulvar intraepithelial neoplasia and related to high-risk human papillomavirus (HPV) infection with high grade squamous intraepithelial lesion (HSIL) as precursor. The aim was to compare the predilection site and survival of HPV-related to non HPV-related vulvar SCCs.

METHODS

Data of patients treated for primary vulvar SCC at the Radboudumc between March 1988 and January 2015 were analyzed. All histological specimens were tested for HPV with the SPF₁₀/DEIA/LiPA₂₅ system assay and p16^INK4a staining was performed using CINtec® histology kit. Vulvar SCCs were considered HPV-related in case of either >25% p16^INK4a expression and HPV positivity or >25% p16^INK4a expression and HSIL next to the tumor without HPV positivity. Tumor localization, disease specific survival (DSS), disease free survival (DFS) and overall survival (OS) of patients with HPV-related and non HPV-related vulvar SCC were compared.

RESULTS

In total 318 patients were included: 55 (17%) had HPV-related (Group 1) and 263 (83%) had non HPV-related vulvar SCC (Group 2). Tumors in Group 1 were significantly more often located at the perineum compared to Group 2, 30% and 14%, respectively (p=0.001). The DSS, DFS and OS were significantly better in HPV-related than in non HPV-related vulvar SCC patients.

CONCLUSION

HPV-related vulvar SCCs are more frequently located at the perineum and have a favorable prognosis compared to non HPV-related vulvar SCCs. Both localization and HPV-relation could explain this favorable prognosis. HPV-related vulvar SCC seems to be a separate entity.

Immunohistochemistry in Gynecologic Pathology: An Example-Based Practical Update

CONTEXT

- Immunohistochemical stains are routinely applied in the pathology diagnostic workup of gynecologic lesions. The rapidly expanding repertoire of available markers helps in refining the diagnostic criteria for each disease entity; however, limitations and pitfalls exist.

OBJECTIVE

- To provide a practical, relevant update on the use of immunohistochemistry for commonly encountered differential diagnoses in gynecologic pathology.

DATA SOURCES

- Literature review and authors' diagnostic experience.

CONCLUSIONS

- Immunohistochemistry is a helpful adjunct tool in gynecologic pathology. Although the primary application is in the diagnostic workup, novel prognostic and predictive markers, and immunostains to screen for genetic cancer syndromes, have also been recently introduced in the field.

Pigmented Paraaxillary Located "Complex" Basal Cell Carcinoma Imitating clinically irritated Melanocytic Lesion - Succesfull Surgical Approach in Bulgarian Patient

BACKGROUND

Basal cell carcinoma (BCC) is the most frequently encountered neoplasm worldwide. While nodular BCC is the most frequent clinical subtype, other forms of BCC, such as superficial, cystic, morpheiform, infiltrative, and pigmented may also be encountered.

CASE PRESENTATION

We present the case of a 67-year-old male with a relatively well-defined infiltrative, pigmented plaque with multiple colours and peripheral growth situated in the right axillary region. The histopathologic examination performed after complete surgical excision of the tumour revealed a complex pigmented BCC with macronodular, fibroepithelioma-like, cystic, focally infiltrative and basosquamous features.

CONCLUSION

Uncommon locations of BCCs in sun-protected areas such as the axillary region require a higher degree of suspicion for diagnosis. The complex histology of the presented case, including subtypes with differing biologic attributes, emphasises the importance of histopathological examination in the diagnosis and therapeutic management of BCC.

The Natural History of Vulvar Intraepithelial Neoplasia, Differentiated Type: Evidence for Progression and Diagnostic Challenges

Squamous cell carcinoma of the vulva (SCCV) develops through either human papillomavirus (HPV)-dependent or HPV-independent pathways. Approximately 60% of SCCV arise independently of HPV, commonly in a background of an inflammatory dermatosis, particularly lichen sclerosus. The likely direct precursor to most of these lesions is vulvar intraepithelial neoplasia (VIN), differentiated type (dVIN), although the evidence is largely circumstantial. There are few reports of progression to carcinoma, and the natural history of this pathway is not well understood. Nevertheless, dVIN is widely regarded as a potentially aggressive lesion. We identified dVIN adjacent to SCCV in 97 of 212 women (45.8%). Twenty-four of the 97 women (24.7%) had biopsies performed at least 6 mo before presentation with SCCV; slides for 47 biopsies from 21 women were available for review. dVIN was identified in 18 biopsies from 8 women (38.1%), which in 14 biopsies had been previously unrecognized. The subsequent cancer developed in the same region as the previous biopsy showing dVIN in 6 of the 8 women. The median interval between biopsy and invasive cancer was 43.5 mo (range, 8-102 mo). dVIN-associated SCCV was strongly associated with both lichen sclerosus, and HPV-negative status compared with usual type VIN (relative risk=38.35 (9.755-150.8) and 0.06485 (0.02764-0.1522), respectively). This study adds to the evidence linking dVIN with SCCV, and indicates that both clinical and histologic underrecognition contribute to the apparent rarity of dVIN as a solitary diagnosis. The morphologic spectrum of dVIN is likely to be wider than commonly appreciated; however, histologically defining the lower threshold is difficult and controversial.

Differentiated Vulvar Intraepithelial Neoplasia: What Criteria Do We Use in Practice?

OBJECTIVES

We sought to recognize the working diagnostic criteria for differentiated vulvar intraepithelial neoplasia (dVIN) among expert pathologists in the field. We also sought the frequency of definitive diagnosis, terminology of equivocal lesions, and views on dVIN's biological significance.

METHODS

Respondents ranked 26 histological and 8 ancillary studies and 5 clinical findings as "essential," "nonessential but strongly supports diagnosis," "possibly supports diagnosis," "weighs against diagnosis" or "uncertain significance or noncontributory." Consensus was defined as 75% agreement. They were asked about diagnosing dVIN on partially sampled lesions, terminology for uncertain lesions, frequency of diagnosis of dVIN relative to uncertain lesions, and if dVIN a is a precursor to an invasion.

RESULTS

Twenty-three completed the survey. Only "basal layer atypia" met consensus (86%) as essential. Consensus criteria for being at least strongly supportive of dVIN were "basal layer hyperchromasia," "presence of basal layer mitoses," and "large keratinocytes with abundant eosinophilic cytoplasm." Only "block-like positivity with p16" or positive HPV specific studies weighed against the diagnosis by consensus. Approximately 87% diagnosed dVIN on partially sampled lesions. Squamous cell hyperplasia with atypia was the most frequent terminology used for uncertain lesions; 87% felt dVIN is a precursor to invasion.

CONCLUSIONS

Only basal layer atypia was considered diagnostically essential by consensus. Additional criteria that strongly support the diagnosis include changes affecting the basal layer and abundant eosinophilic keratinocytic cytoplasm. There was no consensus on ancillary study findings to confirm dVIN. Most would diagnose dVIN on a partial sample. Most consider dVIN a precursor to invasion.

Squamous precursor lesions of the vulva: current classification and diagnostic challenges

Growing evidence has established two major types of vulvar intraepithelial neoplasia (VIN), which correspond to two distinct oncogenic pathways to vulvar squamous cell carcinoma (VSCC). While the incidence of VSCC has remained relatively stable over the last three decades, the incidence of VIN has increased. VIN of usual type (uVIN) is human papillomavirus (HPV)-driven, affects younger women and is a multicentric disease. In contrast, VIN of differentiated type (dVIN) occurs in post-menopausal women and develops independent of HPV infection. dVIN often arises in a background of lichen sclerosus and chronic inflammatory dermatoses. Although isolated dVIN is significantly less common than uVIN, dVIN bears a greater risk for malignant transformation to VSCC and progresses over a shorter time interval. On histological examination, uVIN displays conspicuous architectural and cytological abnormalities, while the morphological features that characterise dVIN are much more subtle and raise a wide differential diagnosis. On the molecular level, dVIN is characterised by a higher number of somatic mutations, particularly in TP53. Here we review the classification, epidemiology, clinical features, histomorphology, ancillary markers and molecular genetics of both types of VIN, and discuss the morphological challenges faced by pathologists in interpreting these lesions.

Usual vulval intraepithelial neoplasia in HIV-positive women - a case series

Usual or undifferentiated type vulval intraepithelial neoplasia (VIN) is more common in young women and is usually associated with high-risk human papillomavirus infection. It is associated with the development of basaloid or warty squamous cell carcinoma. Studies have shown that HIV-positive women have an increased risk of VIN and invasive vulval carcinoma, but there is a paucity of data about this cohort of women. The objective of this study was to describe the clinical features and treatment responses of HIV-positive women diagnosed with VIN in a specialist vulval dermatology clinic. HIV-positive women diagnosed with VIN from 2007 to 2013 were retrospectively identified. Data were collected on demographics, clinical features, treatments and outcomes. Seven cases were retrospectively identified. The median CD4 cell count at presentation was 500 cells/mm³ (range 59-761). Five had multifocal VIN. Five were treated with imiquimod alone, one had surgical excision and one patient was treated with imiquimod and surgery. Five of the seven had complete resolution of disease. HIV-positive patients with VIN had good responses to treatment with imiquimod. They were likely to be stable on combination antiretroviral therapy at presentation, have multifocal disease and concurrent vaginal, anal or cervical intraepithelial neoplasia.

Histopathogenesis of non-HPV-related differentiated oral squamous intraepithelial neoplasia

INTRODUCTION

A study of immunohistopathologic and cytohistopathologic changes of the parabasal/basal layers in the differentiated squamous intraepithelial neoplasia (DSIN) may elucidate the histopathogenesis and reveal changes aiding early diagnosis and grading of the lesion.

MATERIALS AND METHODS

A total of 55 consecutive resection specimens of nonbasaloid squamous cell carcinoma of the anterior oral cavity and 8 biopsies before resections displaying DSIN in the overlying squamous epithelium were examined.

RESULTS

Squamous epithelium that is continuous/immediately adjacent to invasive squamous cell carcinoma (type 1) and the more peripheral (type 2) epithelium of resection specimens displayed consistent changes in the parabasal/basal layers: (A) cytologic atypia with proliferation of parabasal cells with downward expansion causing reactive proliferation of the basal cell layer in the early stage, invading the basal layer in the late stage; (B) disordered nuclear/cytoplasmic arrangement; (C) "Cobblestone" appearance. Immunoreactivity for TP53 and Ki67 was helpful in the diagnosis. The epithelial spectrum of changes decreased as one moved from type 1 to type 2 lesions. Five out of 8 biopsies showed type 1 lesions (followed by resection in a period of 11±6 mo) and 3 showed type 2 lesions (followed by resection in a period of 55±20 mo). In addition, resections were margin positive for type 2 lesions in 5 cases associated with recurrence at the site of resection during a period of 69±9 months.

CONCLUSIONS

DSIN is characterized by a proliferation of neoplastic parabasal cells with dyskeratosis, downward expansion/pushing of the basal layer with elongation of rete ridges. We proposed grading of DSIN based on the changes of the parabasal/basal layers.

An update on vulvar intraepithelial neoplasia: terminology and a practical approach to diagnosis

There are two distinct types of vulvar intraepithelial neoplasia (VIN), which differ in their clinical presentation, aetiology, pathogenesis and histological/immunophenotypical features. One form driven by high-risk human papilloma virus infection usually occurs in young women and has been termed classic or usual VIN (uVIN). The other, not related to viral infection, occurs in postmenopausal women with chronic skin conditions such as lichen sclerosus and lichen simplex chronicus and is termed differentiated or simplex-type VIN. The latter is the precursor lesion of the most common type of squamous cell carcinoma (SCC) in the vulva, namely keratinizing SCC (representing 60% of cases). In contrast, uVIN usually gives rise to basaloid or warty SCC (40% of cases). The histological features of uVIN are similar to those of high grade lesions encountered in other lower anogenital tract sites (hyperchomatic nuclei with high nuclear to cytoplasmic ratios and increased mitotic activity). However, differentiated VIN has very subtle histopathological changes and often escapes diagnosis. Since uVIN is driven by high-risk human papilloma virus infections, p16 immunohistochemistry is diffusely positive in these lesions and is characterized with a high Ki-67 proliferation index. In contrast, differentiated or simplex-type VIN is consistently negative for p16 and the majority of the cases harbour TP53 mutations, correlating with p53 positivity by immunohistochemistry.

Squamous Cell Carcinomas of the Anterior Oral Cavity Are Commonly Associated With Simplex (or Differentiated) Oral Intraepithelial Neoplasia

Introduction: We investigated the occurrence of differentiated oral intraepithelial neoplasia (DOIN) that met the criteria for differentiated intravulvar neoplasia, associated with invasive squamous cell carcinoma (SCC) of the anterior oral cavity, and its clinicopathologic significance. Materials and Methods: Sixty-nine consecutive cases of SCC of the anterior oral cavity were categorized into 2 groups: group A comprised SCC associated with DOIN; Group B consisted of cases associated with classical SCC in situ. Results: Fifty-five cases (80%) were classified as group A, or DOIN lesions, with only 14 (20%) as group B. All cases were associated with invasive SCC, except 2 cases in group B. Squamous epithelium continuous or adjacent to invasive SCC displayed consistent changes in the parabasal and basal layers with (1) cytologic atypia with proliferation of parabasal cells in downward expansion causing reactive proliferation of the basal cell layer in early stage and invading the basal layer in late stage, (2) disordered nuclear/cytoplasmic arrangement, and (3) a “cobblestone” appearance characterized by prominent intercellular spaces and cytoplasmic density involving the entire cell (dyskeratosis) of the parabasal layer. p53 and Ki67 immunostaining revealed linear reactivity mainly in the parabasal layer. Conclusions: DOIN lesions are frequently associated with invasive SCC of anterior oral cavity. Due to the subtle histopathologic changes, DOIN lesions pose potential diagnostic difficulty with differentiation from mild dysplasia or reactive atypia.

Phosphorylated S6 as an immunohistochemical biomarker of vulvar intraepithelial neoplasia

As life expectancy lengthens, cases of non-viral-associated vulvar squamous cell carcinoma and its precursor lesion, so-called differentiated vulvar intraepithelial neoplasia (VIN), continue to increase in frequency. Differentiated VIN often is difficult to recognize and failure to detect it before invasion results in morbidity and mortality. Thus, identification of a reliable biomarker for this type of lesion would be of great clinical benefit. Our recent studies have identified activation (ser235/236 phosphorylation) of ribosomal protein S6 (p-S6) in basal epithelial cells as an event that precedes and accompanies laminin γ(2) overexpression in most preinvasive oral dysplasias. To test this as a potential biomarker of vulvar dysplasia, we immunostained seven differentiated VINs and nine papillomavirus-related 'classic' VINs, most of which were associated with carcinoma, for p-S6. All carcinomas, all differentiated VINs, and most classic VINs contained regions of p-S6 staining in the basal layer, whereas basal and parabasal cells of normal vulvar epithelium and hyperplastic and inflamed lesions lacking cellular atypia were p-S6 negative. Laminin γ(2) was expressed in a subset of VINs, always occurring within basal p-S6 positive regions, as we had found previously for oral dysplasias. Lichen sclerosus is considered a potential precursor of vulvar carcinoma. Two lichen sclerosus lesions of patients with a concurrent carcinoma and one of six lichen sclerosus lesions without atypia or known concurrent carcinoma were basal p-S6 positive. In summary, there is a distinct difference in p-S6 basal cell layer staining between benign and neoplastic vulvar squamous epithelium, with consistent staining of differentiated VIN and of some lichen sclerosus lesions. These results support further studies to assess the potential of p-S6 as a biomarker to identify vulvar lesions at risk of progressing to invasive cancer.

Interobserver variability and the effect of education in the histopathological diagnosis of differentiated vulvar intraepithelial neoplasia

No published data concerning intraobserver and interobserver variability in the histopathological diagnosis of differentiated vulvar intraepithelial neoplasia (DVIN) are available, although it is widely accepted to be a subtle and difficult histopathological diagnosis. In this study, the reproducibility of the histopathological diagnosis of DVIN is evaluated. Furthermore, we investigated the possible improvement of the reproducibility after providing guidelines with histological characteristics and tried to identify histological characteristics that are most important in the recognition of DVIN. A total number of 34 hematoxylin and eosin-stained slides were included in this study and were analyzed by six pathologists each with a different level of education. Slides were reviewed before and after studying a guideline with histological characteristics of DVIN. Kappa statistics were used to compare the interobserver variability. Pathologists with a substantial agreement were asked to rank items by usefulness in the recognition of DVIN. The interobserver agreement during the first session varied between 0.08 and 0.54, which slightly increased during the second session toward an agreement between -0.01 and 0.75. Pathologists specialized in gynecopathology reached a substantial agreement (kappa 0.75). The top five of criteria indicated to be the most useful in the diagnosis of DVIN included: atypical mitosis in the basal layer, basal cellular atypia, dyskeratosis, prominent nucleoli and elongation and anastomosis of rete ridges. In conclusion, the histopathological diagnosis of DVIN is difficult, which is expressed by low interobserver agreement. Only in experienced pathologists with training in gynecopathology, kappa values reached a substantial agreement after providing strict guidelines. Therefore, it should be considered that specimens with an unclear diagnosis and/or clinical suspicion for DVIN should be revised by a pathologist specialized in gynecopathology. When adhering to suggested criteria the diagnosis of DVIN can be made easier.

Clinical variants, stages, and management of basal cell carcinoma

Basal cell carcinoma (BCC) is the most common paraneoplastic disease among human neoplasms. The tumor affects mainly photoexposed areas, most often in the head and seldom appears on genitalia and perigenital region. BCC progresses slowly and metastases are found in less than 0.5% of the cases; however, a considerable local destruction and mutilation could be observed when treatment is neglected or inadequate. Different variants as nodular, cystic, micronodular, superficial, pigment BCC are described in literature and the differential diagnosis in some cases could be difficult. The staging of BCC is made according to Tumor, Node, Metastasis (TNM) classification and is essential for performing the adequate treatment. Numerous therapeutic methods established for treatment of BCC, having their advantages or disadvantages, do not absolutely dissolve the risk of relapses. The early diagnostics based on the good knowledge and timely organized and adequate treatment is a precondition for better prognosis. Despite the slow progress and numerous therapeutic methods, the basal cell carcinoma should not be underestimated.

Treatment failure in patients with HPV 16-induced vulvar intraepithelial neoplasia: understanding different clinical responses to immunotherapy

Failure of the immune system to launch a strong and effective immune response to high-risk HPV is related to viral persistence and the development of anogenital (pre)malignant lesions such as vulvar intraepithelial neoplasia (VIN). Different forms of immunotherapy, aimed at overcoming the inertia of the immune system, have been developed and met with clinical success. Unfortunately these, in principal successful, therapeutic approaches also fail to induce clinical responses in a substantial number of cases. In this review, the authors summarize the traits of the immune response to HPV in healthy individuals and in patients with HPV-induced neoplasia. The potential mechanisms involved in the escape of HPV-induced lesions from the immune system indicate gaps in our knowledge. Finally, the interaction between the immune system and VIN is discussed with a special focus on the different forms of immunotherapy applied to treat VIN and the potential causes of therapy failure. The authors conclude that there are a number of pre-existing conditions that determine the patients' responsiveness to immunotherapy. An immunotherapeutic strategy in which different aspects of immune failure are attacked by complementary approaches, will improve the clinical response rate.

[HPV-associated alterations of the vulva and vagina. Morphology and molecular pathology]

Non-neoplastic HPV-induced alterations of the vulva and vagina are frequent. The traditional three-tier grading system of vulvar intraepithelial neoplasia (VIN) will be replaced by the definition of usual and simplex type of VIN. The usual type is characterized by a strong association to high-risk HPV infections, the occurrence at younger age and multifocality, mostly associated with non-keratinizing squamous cell carcinoma. The differentiated (or simplex) type is rare and shows an association to older age and p53 alterations and is typically diagnosed co-incidentally with keratinizing squamous cell carcinoma. Vaginal intraepithelial neoplasia (VAIN) is still graded into VAIN 1-3 where VAIN 1 and 2 are mostly associated with low-risk HPV infections and a high spontaneous regression rate whereas VAIN 3 represents a high-risk HPV-associated lesion with capable progression into (micro-)invasive carcinoma. The differential diagnosis between a non-neoplastic condylomatous lesion and VIN common type and VAIN may be aided by p16 immunohistochemistry. The HPV-associated invasive vulvo-vaginal cancers are verrucous carcinoma (low-risk HPV) and the high-risk HPV-induced (non-keratinizing) squamous cell carcinoma (NOS), the condylomatous (warty) carcinoma and the very rare vaginal squamo-transitional carcinoma.

Screening and follow up of vulval skin disorders

Vulval squamous cell carcinoma is relatively rare; however, up to 20% of women have significant vulval symptoms during their lifetime. Formal screening programmes for vulval disease have not been established. The evidence for the use of vulval cytology and vulvoscopy is reviewed. No randomised-controlled trials have compared follow-up regimens, and although a few consensus documents have been published, formal guidelines are lacking in Grade A evidence. With increasing pressure on healthcare resources, the possibility of identifying high-risk groups to optimise the use of follow up in specialist clinics is explored. Vulval disease is uncommon and there is no evidence that screening would decrease incidence. If high-risk groups can be identified, follow up should take place in specialised vulval clinics with experienced clinicians who are trained in vulval disease. Women with uncomplicated vulval conditions should be discharged to patient-initiated follow up or primary care. Central to the reduction of mortality and morbidity is increased awareness of vulval conditions among women and improved education of healthcare professionals, with particular understanding of the importance of physical examination.

Pathology of Vulvar Neoplasms

Carcinoma of the vulva is an uncommon malignant neoplasm (approximately one-fifth as frequent as cervical cancer) and represents 4% of all genital cancers in women. Approximately two-thirds of cases occur in women older than 60 years, and squamous cell carcinoma is the most common histologic type. Several different subtypes of squamous cell carcinoma have been described in the vulva; however, in terms of etiology, pathogenesis, and histologic features, most carcinomas belong to one of two categories: keratinizing squamous cell carcinomas associated with chronic inflammatory skin disorders, and basaloid or warty carcinomas related to infection with high oncogenic risk human papillomaviruses. Glandular neoplasms of the vulva arise from the vulvar apocrine sweat glands (papillary hidradenoma and Paget disease) or the Bartholin gland and their cause is not known.

[Pathoanatomical preparation and reporting of specimens from precancerous lesions and carcinomas of the vulva]

On the basis of varying morphology and pathogenesis, two types of vulvar intraepithelial neoplasias (VIN) have been defined: the common type (approximately 98%), classic VIN, is characterised by strong association to high-risk HPV infection (up to 90%), occurrence at younger age (median age 30-40 years) and multifocality. The differentiated (or simplex) type is rare (1%-2%) and is associated with older age (median age 65 years) and p53 alterations. It is usually diagnosed in combination with vulvar (keratinizing) squamous cell carcinoma. The classification currently preferred by the WHO in which VIN are classified into VIN 1-3 is to be replaced due to new data and according to a proposal by the International Society for the Study of Vulvovaginal Diseases (ISSVD) which eliminates VIN 1 and combines VIN 2 and 3 to VIN of common or, depending on histopathology, differentiated type. Prognostically relevant factors in vulvar cancer include stage of disease, inguinal lymph node involvement, size of metastatic deposits and presence of extracapsular extension, depth of invasion and distance of the tumor from resection margins. Tumor grade and the presence of lymphovascular space involvement are controversially discussed.