A 57-year-old woman had undergone right hemicolectomy, partial pancreatic head resection, and partial duodenectomy for advanced ascending colon cancer. Owing to a local recurrence, she was referred to our hospital. Percutaneous transhepatic biliary drainage was performed for a malignant biliary obstruction, and the local recurrence was treated with radiotherapy. Systemic chemotherapy was then started, but the patient had a complication of malignant duodenal obstruction 1 year after the recurrence. Only non-contrast-enhanced abdominal computed tomography could be obtained because of the patient’s allergy to the contrast medium (Fig. 1). The size of the recurrence site was estimated to be approximately 5 cm. However, detailed information on the occlusion site was difficult to obtain before the endoscopic treatment. A forward-viewing endoscope was inserted in the duodenum, and the guidewire was advanced through the stenosis (Fig. 2A). Subsequent contrast imaging revealed a dilated intestinal tract (Fig. 2B). However, contrast imaging at the stenosis revealed another lumen, and the first lumen was clarified to be the colon, and the guidewire was passed through the duodenocolonic fistula (Fig. 2C). The guidewire was turned to enter another lumen, a true duodenal lumen (Fig. 2D). As the enteral stent was placed at the papilla of Vater, an uncovered enteral stent (NEXENT Duodenal Pyloric Stent 22 mm × 12 cm; Next Biomedical, Incheon, Korea) was placed at the duodenal obstruction. After the procedure, the patient could take a normal diet (Fig. 3A, B).