Abstract
The patient was a 71-year-old man with prostate cancer who had been receiving endocrine therapy consisting of an anti-androgen and LH-RH agonist. A year after starting therapy, the patient noticed a mass in the left breast, as well as gradual deformation of the breast, and he visited our department. He was diagnosed as having cancer of the left breast and underwent left mastectomy and sentinel lymph node biopsy. The histopathological diagnosis was invasive ductal carcinoma, papillotubular carcinoma, p, ly1, vo, ER(+), PR(-), HER2(0). Postoperatively, the patient continued to receive LH-RH agonist therapy for prostate cancer and began receiving an anti-estrogen as adjuvant therapy. He is currently being followed.
