Adenocarcinoma of mammary-like glands of the vulva: Report of a case and review of the literature.

Mammary-like glands are a poorly recognized structure of normal vulvar skin. Adenocarcinomas arising from these glands are rare and represent a distinct clinicopathologic entity that must be distinguished from metastatic tumors. We reviewed 19 cases reported in the literature and describe a 51-year-old patient with a long-standing nodule on her right interlabial sulcus. Excisional biopsy and Mohs micrographic surgery demonstrated an infiltrating adenocarcinoma of the mammary-like glands involving the dermis and subcutis. On review of all 20 cases, the mean age at diagnosis was 59.6 years, the labia majora were involved in 13 cases (65%), and the mean lesional size was 2.5 cm. The tumor's histologic patterns varied greatly, although the histomorphologic similarity among this neoplasm, sweat gland carcinomas, and invasive extramammary Paget disease suggested a morphologic spectrum among these tumors. Criteria for establishing the diagnosis of adenocarcinoma of mammary-like glands include identifying transition zones between normal mammary-like glands and adenocarcinomatous areas. This tumor is best categorized as a locally aggressive neoplasm with a low risk for widespread metastasis. Use of aggressive surgical therapeutic regimens, particularly in the case of tumors localized to the skin, must be reassessed, especially given the likelihood of long-term morbidity with such regimens. In our patient, successful Mohs micrographic surgery suggests that alternate management may be adopted for tumors localized to the skin, especially in elderly patients.