Biliary tract anatomical variance - the value of MRCP.

Duplication of the common bile duct (CBD) is a rare congenital anomaly of the bile ducts that should be diagnosed prior to surgery in order to optimise management and prevent complications. We report a case of a patient presenting with choledocholithiasis and type Va duplicated extrahepatic bile duct that was missed on ultrasonography. The atypical course prompted further imaging with magnetic resonance cholangiopancreatography (MRCP), which identified the aberrant bile duct and assisted in safe preoperative and operative management. This case highlights the importance of accurate pre-interventional imaging and agrees with the reclassification of duplications of the CBD.