[A case of peritoneal dissemination of postoperative primary duodenal cancer successfully treated by TS-1 therapy].

A 62-year-old man reported to our hospital with serious complaints of abdominal pain, vomiting, and weight loss. An endoscopic examination detected a type 2 tumor of the descending limb of the duodenum. With a diagnosis of adenocarcinoma based on the biopsy finding, the patient was subjected to surgery.