A case of gastric carcinosarcoma with distant metastasis for which chemotherapy with S-1 plus cisplatin was transiently effective

Gastric carcinosarcoma is a very rare tumor for which there is no standard regimen of chemotherapy. We report a case of a 61-year-old woman having gastric carcinosarcoma with liver and lymph node metastases. She underwent distal gastrectomy due to uncontrollable bleeding from the tumor. Histopathological examination of the resected specimen revealed adenocarcinoma and a sarcomatous component with spindle-shaped tumor cells accompanied by a cartilage formation. She was diagnosed as carcinosarcoma of the stomach with distant metastases, and underwent chemotherapy with S-1 plus cisplatin. Since the liver metastasis shrank once, the treatment was considered to be effective. After the metastatic lesions progressed, she underwent treatment with doxorubicin plus ifosfamide for second-line chemotherapy, and docetaxel subsequently for third-line chemotherapy. The metastatic lesions progressed rapidly and she died 9 months after diagnosis.