The male breast cancer accounts for nearly 1% of all breast cancer cases and bilateral involvement occurs in less than 2% of the cases. Estrogen treatment for prostate cancer is a risk factor for primary breast cancer. Bilateral breast carcinomas were found in a 79-year-old Brazilian black man, following prostate cancer treatment with estrogen. Prostate cancer metastases could be found in breast tissue, and might be indistinguishable from primary breast tumours on histological evaluation without immunohistochemistry. Coexistence of prostate cancer with breast cancer increases future-longevity concerns.