We report the case of a 66 year-old man who developed acute necrotizing pancreatitis. The usual etiologies of acute pancreatitis were easily excluded. Endoscopic retrograde cholangiopancreatography demonstrated a 10 mm diameter filling defect in the distal common bile duct. After endoscopic sphincterotomy, a polypoid tumour which appeared to arise from the common bile duct was delivered through the wound. Diathermic resection of the tumor was performed. Microscopic examination disclosed papillary adenoma, without histologic signs of malignancy. Follow-up was favorable.