S3425 A Very Rare Bile Duct Anatomy Complicated by Stones: Right Anterior Segmental Bile Duct Draining Directly Into Cystic Duct

Introduction: Right anterior segmental bile duct draining directly into the cystic duct is a rare occurrence. This variation has only been reported a handful of times in the literature. Case Description/Methods: A 40 year-old woman presented with 4 day duration of abdominal pain associated with fatty foods. Workup demonstrated dilated bile duct to 16 mm on ultrasound, along with elevated total bilirubin of 5.2 mg/dL. Initial endoscopic retrograde cholangiopancreatography (ERCP) demonstrated multiple filling defects in the common bile duct (CBD) and cystic duct (CD). Right anterior biliary system could not be fully opacified but was initially thought to represent an under-filing duct with a low insertion. Following CBD stone removal, stent was placed to protect against possible migration of CD stones. During cholecystectomy, the duct anatomy again could not be clarified. Given this, CD was ligated close to the gall bladder neck, and its stones were left in situ. Repeat ERCP was performed. Removal of CD stones via electrohydraulic lithotripsy allowed for definitive delineation of bile duct anatomy: right anterior segmental bile duct drained directly into CD, with right posterior bile duct arising from the left bile duct. Discussion: Anatomic variations to bile duct are common, and most are well classified. However, this is an extremely rare un-classified variation which has been reported only few times. Care must be taken to recognize these variations to avoid possible catastrophic complications during cholecystectomy or during transplant.