[Pancreaticoduodenectomy performed in a patient with transverse colon cancer associated with a duodenal fistula - a case report].

: A 71-year-old man with a positive fecal occult blood test was diagnosed with transverse colon cancer and referred to our hospital. Colonoscopy revealed type II transverse colon cancer with circumferential involvement. Contrast-enhanced computed tomography (CT)revealed a tumor with an unclear boundary in the pancreas. No metastases to the liver or lungs were detected, and there were no significantly enlarged regional lymph nodes. During open surgery, the tumor of the transverse colon was found to have formed a mass in the pancreatoduodenum, and it was difficult to separate them. As curative resection was considered possible, resections of both the pancreatoduodenum and transverse colon cancer were performed. Laboratory findings revealed fistula formation between the transverse colon cancer and the duodenum. The cancer was diagnosed as stageII, T4bN0M0, and R0 surgery was successfully performed. The patient was alive without recurrence 14- months after the surgery. Colorectal cancer is more likely to advance locally and directly invade the surrounding organs. However, fistula formation with the duodenum has rarely been reported, occurring at an estimated incidence of 0.1%. Such tumors are typically large; however, metastases rates to the lymph nodes are low. Histopathological examination of the resected specimen revealed a severe inflammatory adhesion, and fistula formation between the traverse colon and the duodenum. There was no evidence of invasion of the lymphatic system or blood vessels, which enabled us to perform a high curative surgery. We propose that it is important to consider high curative resection with positive lymph node dissection for cases of colorectal cancer associated with duodenal fistula formation.