Adenocarcinoma of Mammary‐Like Glands of the Vulva

Abstract

Mammary‐like glands are a poorly recognized structure of the normal vulvar skin. Adenocarcinomas occur rarely in these glands and represent a distinct clinicopathologic entity that must be distinguished from metastatic tumors. We present a case of a 51‐year‐old patient with a long‐standing nodule on her right labium majus. Excision with subsequent Mohs micrographic surgery revealed an infiltrating adenocarcinoma of the mammary‐like glands involving the dermis and subcutis. We review all cases thus far reported (including the case presented herein) and identify important clinical and morphologic features of this tumor. A significant histopathological and immunohistochemical overlap between this neoplasm, sweat gland carcinomas, and invasive extramammary Paget’s disease was recognized; suggesting the existence of a morphologic spectrum between these entities. Criteria for establishing the diagnosis of adenocarcinoma of mammary‐like glands are reviewed, including the importance of identifying transition zones between normal mammary‐like glands and malignant glands. We believe that this tumor is best categorized as a locally aggressive neoplasm with a low metastatic potential and death from disease is uncommon. The successful treatment of this case by Mohs micrographic surgery suggests that an alternate management approach may be adopted for these tumors, particularly in elderly patients.