A Case of Choledochocele Unclassifiable by Sarris’s Classification Characterized by the Serial Images of Endoscopic Retrograde Cholangiopancreatography [ERCP]

A 74-year-old Japanese housewife was shown to have a large, smooth-surfaced, protruding, subpedunculated tumor covered with the normal-appearing mucosa on the posteromedial wall of the mid descending part of the duodenum immediately oral to the papilla of Vater by endoscopy. ERCP demonstrated the normal main and accessory pancreatic ducts. Just after abruptly contracted, the terminal common bile duct [CBD] showed a piriform dilatation correspondent to the duodenal tumor and tapered off to drain into the duodenal lumen without forming a common channel but through the same papillary orifice with the main pancreatic duct [MPD]. She was diagnosed with choledochocele unclassifiable by Sarris’s categorization. Even fully distended by infusion of contrast medium, the cyst did not compress the MPD. Remaining asymptomatic, the lesion was left untreated. She has kept an uneventful course for 4 years ever since. It is important to characterize the topographic relationships of the cyst among the surrounding structures in order to definitely classify the anomaly and to predict development of probable complications by analyzing the serial images of ERCP.