29 巻 (2015) 5 号 p. 870-873
Congenital biliary dilatation (CBD) is a congenital malformation involving both extrahepatic bile duct dilatation and pancreaticobiliary maljunction (PBM). Although pathogenesis of bile duct dilatation is unknown, PBM causes reciprocal reflux between the pancreatic juice and bile and results in various biliary and pancreatic pathologies. For a diagnosis of CBD, both abnormal dilatation of the bile duct and PBM must be evident. Bile duct dilatation should be diagnosed based on age-related limits on the maximum diameter of the common bile duct using diagnostic imaging (e.g., ultrasonography, magnetic resonance cholangiopancreatography, and multiplanar reconstruction imaging by multidetector row computed tomography). Endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiopancreatography, and operative cholangiography would be avoided as bile duct measurement tools. Typical concomitant anatomical characteristics of extra- and intra-hepatic bile ducts should be also considered when diagnosing CBD. Diagnosis of PBM, an abnormally long common channel, and/or an abnormal union between the pancreatic and bile ducts must be established by various radiological imaging.