Sebaceous carcinoma of the vulva.

Extraocular sebaceous carcinoma (SC) is a rare tumor usually found on the head and neck. A 78 year old Japanese female who had an asymptomatic vulvar tumor is reported here. The excised specimen showed SC with metastasis to the inguinal lymph nodes. This is the fourth reported case of SC arising from female genitalia, and the second case that apparently arose from the labia minora. Contrary to the previously reported cases, tumor cells in the present case had abundant glycogen. Thus, differential diagnosis of SC from metastatic renal cell carcinoma is difficult morphologically because both of them have glycogen and lipid. Intraepidermal invasion of tumor cells has been reported in SC, but a suspected lesion of this phenomenon in the present case was proved to be histiocytic infiltration by immunohistochemistry using anti-CD 68 antibody.