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Case Reports

Abstract

We report the case of a 41-year old female with a 1.4 cm tumor on her left vulva that approaches the clitoral hood. Excisional biopsy of the left labia minora and majora showed dermal-based tumor with infiltrative basaloid nests with adjacent vulvar intraepithelial neoplasia. There was prominent necrosis and some of the nests demonstrated sebaceous differentiation. VIN2 was also noted in the adjacent epithelium. Based on histology, the differential diagnosis included poorly differentiated basaloid squamous cell carcinoma (SCC) or a basal cell carcinoma (BCC), both with sebaceous differentiation and sebaceous carcinoma. The tumor was positive for p40, p63, BerEP4, androgen receptor (focal) and adipophilin (focal). p16 showed block positivity and p53 demonstrated a wild-type staining pattern. By in situ hybridization, the tumor was positive for high-risk HPV and negative for Gli-1. The patient proceeded with vulvectomy with removal of clitoris as well as bilateral inguinal lymph node biopsy. The lack of Gli-1 expression rules out BCC and due to the presence of VIN2 the tumor was diagnosed as HPV-associated SCC with sebaceous differentiation. HPV-associated vulvar carcinoma with sebaceous differentiation is rare, with only 3 cases reported so far. The biologic significance of sebaceous differentiation in SCC is yet to be established.