Ectopic Male Breast Cancer in the Perineum: A Case Report.

Ectopic breast tissue and male breast cancer are both very rare diseases with only a few reports in the literature. Here, we present the first case of ectopic male breast cancer in the perineum. The patient was a 70-year-old man with a palpable mass in the perineum. A wide local excision and inguinal lymph node dissection revealed invasive breast carcinoma of no special type involving the skin and subcutis, and inguinal lymph node metastases. Immunohistochemical staining showed that the tumor cells were strongly positive for estrogen and progesterone receptors and negative for human epidermal growth factor receptor 2. Moreover, no p53 overexpression was observed. Herein, the clinical and pathologic features, as well as a review of ectopic male breast cancer are discussed.