DILATED COMMON CHANNEL SYNDROME - ENDOSCOPIC DIAGNOSIS, TREATMENT, AND RELATIONSHIP TO CHOLEDOCHOCELE FORMATION

Background: Choledochoceles (type III biliary cysts) are cystic dilati ons of the terminal common bile duct or common pancreatobiliary channe l. Although no size criteria have been defined, it is generally assume d these must be large. However, we describe patients who do not meet t he perceived size criteria for choledochoceles, but who nonetheless ha ve a dilated common pancreatobiliary channel. Methods: We reviewed the presenting symptoms, endoscopic and radiographic findings, and respon se to endoscopic therapy of patients meeting our criteria for the dila ted common channel syndrome. Results: Of 2847 patients undergoing ERCP , 100 (3.5%) had the dilated common channel syndrome. Common presentin g symptoms and signs included abdominal pain in 97%, abnormal liver fu nction test(s) in 66%, and a history of acute or recurrent pancreatiti s in 46%. A bulge was visible above the papilla in 88%, with a dilated common bile duct in 54% and a dilated pancreatic duct in 28%. After e ndoscopic unroofing of the common channel, 77% had complete and long-l asting resolution of symptoms, 18% had partial or transient improvemen t, and 5% had no change. Conclusions: Although classic choledochoceles are rare, a lesser degree of dilation of the common channel is more f requent than generally appreciated. We postulate that this finding rep resents an ''incomplete,'' acquired form of choledochocele, possibly c aused by underlying papillary stenosis. Whatever the etiology and appr opriate term, the presence of a dilated common channel predicts a high rate of clinical response to endoscopic therapy.