Double common bile duct visualized by SpyGlass cholangioscopy.

ly rare anomaly of the biliary tract system, which was first described by Vesalius in 1543 [1]. Recent advances in radiologic examinations have facilitated the correct diagnosis and management of this condition, but visualization of the anomaly using cholangioscopy has not been reported [2]. We report the finding of a double common bile duct with ectopic drainage into the duodenal bulb, which was successfully visualized using the SpyGlass cholangioscope (Boston Scientific, Natick, Massachusetts, USA). A 69-year-old man was referred to our institution for endoscopic treatment of choledocholithiasis and a duodenal stricture of unknown origin. First, a duodenoscope was advanced into the second portion of the duodenum after a balloon dilation of the stricture had been performed. Endoscopic retrograde cholangiopancreatography (ERCP) revealed multiple common bile duct stones and an aberrant bile duct opening into the duodenal bulb (●" Fig. 1). After the stones had been successfully removed by endoscopic papillary balloon dilation, a SpyGlass cholangioscope was advanced into the ectopic bile duct. Cholangioscopic imaging revealed normal bile duct mucosa (●" Fig. 2;●" Video 1). Finally, duodenoscopy revealed a slightly depressed lesion adjacent to the duodenal stricture (●" Fig. 3); this was confirmed after injection of contrast to be the ectopic opening of the double bile duct (●" Fig. 4). It is possible that the duodenal stricture may have been caused by continuous exposure to the bile from the ectopic opening. He was diagnosed as having a type II double common bile duct according to the Goor’s classification [3]. Preoperative diagnosis of a double common bile duct is not easy because of its rarity [4]. SpyGlass cholangioscopy has been reported to be a feasible management of various pancreatobiliary diseases [5]. In this case it enabled us to examine the double bile duct precisely and distinguish the ectopic bile duct from a bilioenteric fistula. SpyGlass cholangioscopy is a useful technique for the correct diagnosis of double common bile duct.