Fig. 1. (A) Abdominal computed tomography showed a 1.4 cm cystic mass (asterisk) at the ampullary level. (B) Initial endoscopic retrograde cholangiopancreatography demonstrated smooth bulging of the major duodenal papilla. (C) Type III periampullary diverticulum was noted. Orifice was well seen. (D) Second endoscopic retrograde cholangiopancreatography showed persistent bulging of the major duodenal papilla. (E) Deep bile duct cannulation was successful after infundibulotomy. (F) Cholangiography showed saccular dilatation at the ampullary level.