A Case of Male Breast Cancer Occuring Away from the Nipple

Abstract

A 64-year-old man presented to our hospital after noticing a left chest mass. Ultrasonography showed a 15-mm solid mass, 5 cm away from the nipple at the 11 o'clock position. MRI revealed a linear structure without enhancement between the irregular shaped tumor and the nipple. Invasive ductal carcinoma was diagnosed by a vacuum assisted biopsy. Because of his past-history of chronic obstructive pulmonary disease and pneumonia caused by COVID-19 infection 3 months earlier, to avoid lung damage by postoperative irradiation, mastectomy and sentinel lymph node biopsies were performed instead of breast conserving surgery. Postoperative pathological examination revealed the duct-like structure between the nipple and the tumor that was diagnosed as invasive ductal carcinoma, pT1b(9mm), pN0(SN), M0, Stage I. Immunohistochemistry showed the positivity of both estrogen and progesterone receptors. As the adjuvant medication therapy, oral tamoxifen for 5 years was chosen. Although most male breast cancers are located under the nipple, few of them have been reported to occur away from the nipple. It is important to recognize that even male breast cancer can develop in sites distant from the nipple.