A clinicopathologic study of choledochal cyst.

Choledochal cyst is quite common in Japan. The etiology of this lesion is not clear, and there remain problems in its treatment as well. Radiologic investigation of the distal common bile and pancreatic ducts was performed by operative cholangiography and endoscopic retrograde cholangiopancreatography. Anomalies at the junction of these ducts were found in all of the patients. Localilzed cystic dilatation of the extra-hepatic bile ducts without intrahepatic bile duct dilatation was produced experimentally by ligation of the distal choledochus in infant rats. Concerning the etiology, we agree with Babbitt's hypothesis that weakness of the choledochal wall is produced by reflux of pancreatic juice via an anomalous choledochopancreatic junction. We think that the stenosis associated with this anomaly is the critical factor. From our follow-up study of 30 cases, we find excision of the cyst to be the most important part of treatment. Choledochal cysts presenting under 6 months of age had clinical symptoms and pathology similar to biliary atresia.