A case of ovarian carcinosarcoma with germline BRCA2 pathogenic variant.

Ovarian carcinosarcoma in hereditary breast and ovarian cancer syndrome is rare. A 43-year-old woman with a family history of prostate and uterine or ovarian cancer had an 8-cm mass in the right ovary. Although computed tomography suggested peritoneal dissemination to the Douglas pouch, she wanted to preserve her fertility; therefore, she underwent a right salpingo-oophorectomy. Histopathological diagnosis was carcinosarcoma consisting of high-grade serous carcinoma and sarcomatous components, including cartilage. Three weeks later, she underwent radical surgery. The disease was classified as advanced stage IIIB (FIGO 2014). A germline BRCA2 pathogenic variant was identified. After postoperative adjuvant chemotherapy, maintenance therapy with a poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor was continued for 25 months without recurrence. A detailed examination of a mass in her left breast at her first visit revealed a ductal carcinoma in situ. PARP inhibitors may be effective as maintenance therapy for advanced ovarian carcinosarcoma with germline BRCA mutations.