Duplication of the extrahepatic bile duct with anomalous union of the pancreaticobiliary ductal system revealed by MR cholangiopancreatography.

MR cholangiopancreatography (MRCP) is a valuable, non-invasive tool for accurate examination of the biliary system. We report a case in which MRCP played a critical role in the diagnosis of a duplication of the extrahepatic bile duct with anomalous union of the pancreaticobiliary ductal system in a patient with hilar cholangiocarcinoma. This variant of a duplication of the extrahepatic biliary system has not been described previously in the literature.