Congenital dilatation of the common bile duct is a disease in which the extrahepatic bile duct, or both the extra and intrahepatic bile ducts, is dilated in various ways. Pancreaticobiliary maljunction is a disease in which the pancreatic duct meets the bile duct outside of the duodenal wall beyond the sphincter Oddi. Recently, these diseases have been thought to be closely related to each other but to be different malformations. Biliary tract carcinoma, especially bile duct carcinoma, is found in about 30% of patients with congenital dilatation of the bile duct. The concomitance of bile and pancreatic juice and their stasis in the biliary tract induce cellular proliferation and reproduction and stimulate genetic alterations in biliary epithelium, which may play an important role in carcinogenesis of the bile duct. Endoscopic retrograde cholangiopancreatography is useful for examining pancreaticobiliary maljunction. The operation is dilated bile duct resection and hepaticojejunostomy, which ensure that pancreatic juice and bile do not mix in the bile duct. Gallbladder carcinoma develops in more than 90% of pancreaticobiliary maljunction without bile duct dilatation.
