An Unusual Case of Human Papillomavirus-Related Anorectal Adenocarcinoma With Progression to Perianal Paget's Disease.

Primary adenocarcinoma of the anorectum, compared with squamous cell carcinoma, is a rarer and more aggressive malignant neoplasm. Infection with human papillomavirus (HPV) has been identified as a causal agent in a variety of tumors, including those of the cervix, head and neck, and anogenital region, especially squamous cell carcinoma. However, the relationship between HPV and anorectal adenocarcinoma has not been well studied. In this article, we report an HPV-related anorectal adenocarcinoma arising in a tubulovillous adenoma in a 76 years old female who presented initially with lower gastrointestinal bleeding. The carcinoma cells were positive for cytokeratin 7 and p16 by immunohistochemistry. High-risk HPV RNA in situ hybridization was positive. A follow-up examination of the anal area showed perianal plaques. Histologically, the excision of the perianal lesion showed intraepithelial infiltration by sheets and clusters of large atypical neoplastic cells. The neoplastic cells showed the same immunoprofile compared with the anorectal adenocarcinoma with p16 and high-risk HPV positivity. The findings are consistent with extramammary perianal Paget's disease secondary to anorectal adenocarcinoma. HPV-related adenocarcinoma in the anorectum is a newly recognized entity and was previously considered clinically indolent. Our case uniquely exhibits adenoma-carcinoma-perianal Paget's disease sequence, which has not been reported before. Our findings suggest that evaluation of the patient's lower genital tract for any HPV-associated lesions and long-term follow-up are required to monitor the disease progression in this type of malignancy.

P16 Expression in Primary Vulvar Extramammary Paget Disease.

P16 immunohistochemistry has been widely used in facilitating the diagnosis of human papillomavirus (HPV)-related usual type vulvar intraepithelial neoplasm. However, studies of p16 expression in primary vulvar extramammary Paget disease (EMPD) are limited. We assessed the p16 expression by immunohistochemistry in 40 cases of primary vulvar EMPD, including 34 cases of intraepithelial vulvar EMPD and 6 cases of invasive vulvar EMPD and correlated p16 expression patterns with disease progression. Overall, p16 expression was present in 36 cases (90%), including 20 cases (50%) with focal staining pattern and 16 cases (40%) with diffuse staining pattern. All 20 cases with focal p16 staining pattern were intraepithelial vulvar EMPD. Diffuse p16 staining pattern was present in 10/30 cases (33.3%) of intraepithelial EMPD and in 6/6 cases (100%) with invasive vulvar EMPD. Negative p16 staining was present in four intraepithelial EMPD cases. Using a highly sensitive RNA in situ hybridization method, we did not detect high-risk HPV in the selected 10 cases with diffuse p16 staining pattern, including 6 cases of intraepithelial EMPD and 4 cases of invasive EMPD. We also observed that intraepithelial EMPD had predominantly cytoplasmic p16 immunoreactivity, whereas nuclear p16 immunoreactivity was mainly seen in invasive EMPD components. Our study demonstrated that the p16 positive immunostaining was seen in the majority of primary vulvar EMPD which is not related to HPV infection. Therefore, knowing the overlapping p16 immunostaining patterns in vulvar EMPD and usual type vulvar intraepithelial neoplasm is important to render the correct diagnosis.

P16 Expression in Extramammary Paget's Disease of the Vulva and Scrotum Is Not Human Papillomavirus Related.

INTRODUCTION: Extramammary Paget disease (EMPD) of the vulva has been shown to express p16 by immunohistochemistry (IHC), however, p16 expression in the vulva and scrotum has not been extensively studied in relation to human papillomavirus (HPV) within EMPD of both the vulva and scrotum. DESIGN: Twenty-two cases of EMPD (vulva, 16; scrotum, 6) were found in our laboratory information system. P16 and HPV IHC were performed. Any p16 reactivity less than 10% was considered negative. HPV in situ hybridization for both low- and high-risk HPV was also performed on all cases. RESULTS: Of the 6 scrotal EMPD, 3 (50%) showed weak to moderate positive reactivity for p16 by IHC. Of the 16 vulvar EMPD, 13 (81%) were positive for p16, with at least moderate (2+) intensity with a mean expression of 33.3% (range = 10% to 80%) and 62% (range = 20% to 95%) in scrotal and vulvar EMPD, respectively. None of the scrotal or vulvar cases showed positive reactivity for HPV either by IHC or in situ hybridization. CONCLUSION: Both vulvar and scrotal EMPD can express p16 by IHC, more commonly vulvar than scrotal; however, no HPV was detected either by IHC or in situ hybridization. EMPD of vulva and scrotum does not appear to be related to HPV, and p16 expression may be regulated through a different mechanism.

BD ProEx C immunostaining in extramammary Paget's disease and perineal melanoma.

The differential diagnosis of perineal biopsies can include squamous intraepithelial lesions, extramammary Paget's disease, and melanoma. Less frequently two of these lesions coexist. BD ProEx C is a recently developed immunoassay that targets expression of two genes shown to be associated with cervical cancer. Immunostaining for ProEx C has been validated in cervical cytology and positive staining has also been shown to be strongly associated with human papilloma virus (HPV)-induced cervical and anal intraepithelial neoplasia in biopsies. We observed positive staining for ProEx C in Paget cells in all of 26 cases of Paget's disease irrespective of tissue site (extramammary, mammary) and in melanoma cells in all of 12 cases of primary perineal melanoma with immunostaining in >50% of malignant cells in 73% of Paget disease cases and 43% of perineal melanoma cases. Positive staining was heterogeneous and exclusively nuclear in all cases. In situ hybridization was negative for low-risk and high-risk HPV subtypes in all Paget and melanoma cases that were tested. Currently neither of these lesions is known to be HPV related although according to the literature the possibility of a role for HPV in melanoma is still unsettled. Relevant literature is reviewed.

Pagetoid squamous cell carcinoma in situ of the vulva: comparison with extramammary paget disease and nonpagetoid squamous cell neoplasia.

Pagetoid squamous cell carcinoma in situ (PSSCIS) is a variant of squamous cell intraepithelial neoplasia. Although PSSCIS is well-documented in the cutaneous skin and esophagus, cases of vulvar PSSCIS are rare. In the vulva, the main differential diagnosis is extramammary Paget disease (EMPD). We report 2 cases of vulvar PSSCIS along with the immunohistochemical and human papillomavirus (HPV) status of this disease compared with primary cutaneous EMPD of the vulva. Although PSSCIS and EMPD share CK7 and CK19 expression, PSSCIS is consistently mucin and carcinoembryonic antigen negative. In contrast to EMPD, both cases of PSSCIS strongly expressed p16 (INK4A) protein, consistent with RB1 protein dysregulation. However, integration of high-risk HPV was found in only 1 of the 2 PSSCIS cases. Given the morphological and immunohistochemical findings, we suggest that PSSCIS arises from a bidirectional stem cell capable of both squamous and glandular differentiation. Additionally, as with nonpagetoid squamous cell neoplasias of the vulvar, integration of high-risk HPV may occur in some, but not all, cases of PSSCIS.

Simultaneous human papillomavirus 6 (HPV 6) -positive condyloma acuminatum, HPV 31-positive Bowen's disease, and non HPV-associated extramammary Paget's disease coexisting within an area presenting clinically as condyloma acuminatum.

An 83-year-old Japanese man presented with multiple verrucous papules clustering on a plaque located on the frontal aspect of the scrotum. Histologically, there were three distinct epithelial changes compatible with condyloma acuminatum, Bowen's disease, and extramammary Paget's disease (EMPD). By in situ hybridization, the zone of condyloma acuminatum was positive for HPV 6 and well demarcated from HPV 31-positive Bowen's disease. EMPD was negative for targeted HPV 6/11/16/18/31/33 probes. Immunohistochemically, Paget's cells expressing cytokeratin 7 were distributed as scattered single cells or clusters mainly in the lower part of the HPV 6/31-positive epithelium. To the best of our knowledge, this is the first reported case of the occurrence of condyloma acuminatum, Bowen's disease, and EMPD within the same lesion.

Analysis of clonality and HPV infection in benign, hyperplastic, premalignant, and malignant lesions of the vulvar mucosa.

To elucidate the pathogenesis of vulvar carcinomas, we studied clonality and human papillomavirus (HPV) infection in vulvar epithelial diseases. Monoclonal composition was demonstrated in all 9 invasive tumors (squamous cell carcinoma [SCC], 6; basal cell carcinoma, 1; malignant melanoma, 2), 15 of 20 cases of vulvar intraepithelial neoplasia (VIN), 7 of 9 cases of Paget disease, 2 of 6 cases of lichen sclerosus (LS), and 2 of 3 cases of squamous cell hyperplasia (SCH); high-risk type HPV was revealed in 5 of 6 SCCs and 17 of 20 VINs. These observations might imply that a subset of cases of LS and SCH result from a neoplastic proliferation, similar to VINs but not related to infection with high-risk type HPV. In 1 case of SCC with concurrent VIN 3 in an adjacent lesion, both lesions showed the same pattern of X chromosome inactivation and the presence of HPV-16 in episomal and integrated forms, suggesting that monoclonal expansion triggered by high-risk type HPV integration is an early event for carcinogenesis of HPV-associated SCC.

Extramammary Paget's disease with superimposed herpes simplex virus infection: immunohistochemical comparison with cases of the two respective diseases.

We describe an extremely rare case of genital Paget's disease with superimposed herpes simplex virus (HSV) infection. We also describe immunohistochemical comparison of this lesion with 19 cases of genital Paget's disease and 12 cases of skin lesions caused by HSV or varicella-zoster virus. The Paget cells expressed simple epithelial keratins (CK7 and CK19) and carcinoembryonic antigen (CEA), but did not express stratified epithelial keratins (CK1, CK2e, CK10, CK5/8, CK14). Conversely, the virus-infected keratinocytes were positive for stratified epithelial keratins but negative for simple epithelial keratins and CEA. In the present case, simple epithelial keratins, stratified epithelial keratins, CEA and HSV were heterogeneously expressed in the ballooning and multinucleated giant cells. These results suggest that these cells were derived from keratinocytes and Paget cells and that the production of many multinucleated giant cells resulted from the virus-mediated cell fusion between Paget cells and neighbouring keratinocytes.