UC Irvine

Accessory male breast cancer (BC) is a rare entity and is associated with poor outcome. We report a 76-year-old patient who was diagnosed with concurrent accessory breast and primary lung cancer, both were positive for somatic BRCA-2 (E1593D) mutation. He received concurrent radiation and platinum-based chemotherapy for lung cancer with good response, but breast cancer progressed in about 8 months, and further progressed after single agent anastrozole in 10 months. Next Generation Sequencing (NGS) of breast cancer was also positive for CCND1 (Cyclin D1) and FGFR1 amplifications. Despite a poor molecular profile of breast cancer, and progression following platinum-based chemotherapy and anastrozole, he was successfully treated with the Cyclin-dependent kinase (CKD) 4/6 inhibitor palbociclib, estrogen-receptor down-regulator fulvestrant and luteinizing hormone-releasing hormone (LHRH) agonist leuprolide with the duration of response of 21 months which has exceeded duration of response to prior treatments. This case is of interest given FDA expanded the approval of palbociclib in combination with AI or fulvestrant for male patients with HR-positive, HER2-negative metastatic breast cancer in Apr. 2019 based on real-world data from electronic health records.