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Abstract

Sebaceous carcinoma is a rare malignancy, particularly when occurring in extraocular site, and may be associated with Muir-Torre syndrome, a condition characterized by sebaceous neoplasms and internal malignancies. To date, fewer than 20 cases of vulvar sebaceous carcinoma have been reported in the literature. We report an additional case of vulvar sebaceous carcinoma in a 68-year-old woman. The patient’s initial biopsy revealed a high-grade squamous intraepithelial lesion, positive for high-risk human papillomavirus by in-situ hybridization (HR HPV-ISH), overlying an atypical proliferation of sebaceous glands. A subsequent reexcision showed a well-circumscribed yet asymmetric proliferation of variably sized sebaceous lobules with varying proportions of basaloid cells and sebocytes, with some lobules comprised entirely of basaloid cells. Moderate cytologic atypia, scattered mitoses and karyorrhexis were observed.  Lesional cells were positive for EMA, androgen receptor, p16, CK5/6, and PRAME by immunohistochemistry, and positive for HR HPV-ISH.  No residual squamous intraepithelial lesion was observed. This case is notable for the concurrent findings of a high-risk HPV-associated high-grade squamous intraepithelial lesion and the presence of high-risk HPV within the sebaceous carcinoma, suggesting a potential link between HPV infection and the development of vulvar sebaceous neoplasms. These findings warrant further investigation into the role of HPV in this rare malignancy.