BACKGROUND: Adenomatous polyposis coli is an autosomal dominant hereditary disorder. Duodenal adenocarcinoma and adenoma, which are extracolonic lesions, not only affect the prognosis of patients but also cause acute pancreatitis.

CASE REPORT: We present the case of a 73-year-old male. He had undergone proctocolectomy for familial adenomatous polyposis and distal gastrectomy (Billroth II reconstruction with Braun anastomosis) for gastric ulcer; he presented with acute pancreatitis caused by ampullary duodenum adenoma. Double-balloon endoscopy showed 2 adenomatous polyps in the major papilla and descending limb of the duodenum. Based on the findings of endoscopy and biopsy, the duodenal polyps were diagnosed as adenomas and classified as Spigelman stage II.

CONCLUSIONS: Our case report suggests that duodenal surveillance is necessary for patients with adenomatous polyposis coli. In addition, surveillance using double-balloon endoscopy is useful for patients with an altered gastrointestinal anatomy.

Keywords: Adenomatous Polyposis Coli, Gastroenterostomy