Pedunculated early carcinoma of supra-ampullary duodenum presenting as acute pancreatitis.

Background. A 43-yr-old man was admitted to our hospital after sudden onset of epigastric pain. He was diagnosed with acute pancreatitis by clinical, laboratory, and radiographic signs. Examinations for the etiology of acute pancreatitis revealed a duodenal tumor arising at the proximal portion of the descending limb, extending by a long stalk, and coming into contact with Vater's papilla. The tumor was snare-resected endoscopically. Histological examination showed an early carcinoma. Extra-ampullary carcinoma of the duodenum should be considered an unusual cause of acute pancreatitis secondary to obstruction of the major duodenal papilla. Endoscopic polypectomy is effective because of the difficulty in making a precise diagnosis by endoscopic biopsy.