[A Case of Undifferentiated Carcinoma of the Sigmoid Colon That Responded to Paclitaxel and Carboplatin Chemotherapy].

We report a case of a 72-year-old woman who was initially diagnosed with ovarian cancer with peritoneal carcinomatosis. Systemic chemotherapy consisting of paclitaxel and carboplatin(TC)was administered. Although a partial response(PR)was achieved after the 4 courses of TC, this regimen was discontinued due to severe adverse events. Ten months after discontinuation of TC, because abdominal CT and colonoscopy showed an intra-tumoral abscess caused by invasion of the tumor to the sigmoid colon, abdominal total hysterectomy, bilateral salpingo-oophorectomy, and a Hartmann's operation were performed to control the disease symptoms. Pathological examination revealed that the tumor was an undifferentiated carcinoma of the sigmoid colon. This case report suggests that the TC regimen may be effective for treating undifferentiated carcinoma of the colon.