Lost opportunity for genetic counseling cause a delayed diagnosis of male breast cancer whose sibling has a BRCA2 pathogenic variant: a case report

Abstract

　The patient is a 70-year-old man. His younger brother had Stage IV male breast cancer, and a companion diagnostic of a PARP inhibitor was performed at another hospital. The result showed that the younger brother had a pathogenic variant of BRCA2. The patient was informed by his younger brother that he was a carrier of a pathogenic variant of BRCA2. However, the patient lived far away from his younger brother and did not go for genetic counseling. Three years later, the patient noticed a lump under the skin on the outside of the right areola. Consequently, he visited his family doctor. However, at that time, he did not inform the doctor about his family history of breast cancer and the genetic test result of his younger brother. The doctor decided to follow up on the lump. The size of the lump at the right breast continued to increase. Thus, four months later, the patient visited his family doctor again. At this time, he told the doctor that his younger brother, three years earlier, had breast cancer and a gene mutation deeply related to breast cancer. At this point, the doctor referred him to our department of breast surgery. The lump was diagnosed as right breast cancer by core needle biopsy. Total right mastectomy and sentinel lymph node biopsy were performed, and the final pathological diagnosis was pT2N1M0 pStage IIB breast cancer. We report a case of delayed diagnosis of male breast cancer without informing family history of male breast cancer with BRCA2 pathogenic variant.