[A Case of Synchronous Bilateral Male Breast Cancer].

A 71-year-old man with right and left mammary tumor came to our hospital. Using needle biopsy, we diagnosed both tumors as ER-positive, PgR-positive, and HER2(1+)invasive ductalcarcinoma. We performed radicalmastectomy and axillary dissection. After surgery, the patient received postoperative chemotherapy, radiotherapy, and hormone therapy. The incidence of male breast cancer has been reported to be<1% of all breast cancer cases; only a few cases of simultaneous bilateral male breast cancer has been reported. Here, we report a rare case of synchronous bilateral male breast cancer.