Curative Surgery for Malignant Sigmoid-Duodenal Fistula Caused by Colon Cancer: A Case Report

A malignant sigmoid colon-duodenal fistula is extremely rare, and optimal management strategies remain unclear.

A 66-year-old man was admitted to a local hospital with melena. Lower gastrointestinal endoscopy identified a circumferential type 3 tumor located in the sigmoid colon. Upper gastrointestinal endoscopy revealed extrinsic tumor invasion into the horizontal portion of the duodenum. Contrast-enhanced abdominal CT demonstrated irregular thickening of the sigmoid colon wall, which appeared to be contiguous with the horizontal portion of the duodenum, with evidence of luminal continuity. Based on a diagnosis of malignant sigmoid-duodenal fistula, the patient underwent open surgery. At laparotomy, the sigmoid colon cancer was found to be directly invading the duodenojejunal flexure, arising from the ligament of Treitz on the left side of the superior mesenteric artery, which made preservation of the duodenum difficult. Therefore, Hartmann's procedure with concomitant segmental duodenectomy was performed while preserving the pancreas. For duodenal reconstruction, a Roux-en-Y jejunal limb was created and anastomosed to the second portion of the duodenum. Additionally, a gastrojejunostomy in the Billroth II configuration was performed.

Malignant invasion of the duodenum is often associated with involvement of major vessels or the need for pancreatic resection, which may render curative resection difficult or excessively invasive. However, segmental duodenectomy with preservation of the pancreas can be a valuable surgical option in selected cases.