Congenital dilatation of the common bile duct in children.--The etiologic significance of the narrow segment distal to the dilated common bile duct.

Radiographic studies of 26 choledochal cyst patients were evaluated. Abnormal junction of the pancreatico-biliary system (PBS) was demonstrated in all patients. The transverse diameter of dilated common bile ducts was closely related to the length of the narrow segment of the distal common bile duct. Common bile ducts had not dilated despite the anomalous junction of PBS during the follow-up period, ranging from 2 to 12 years after choledochocysto -jejunostomy in 7 patients. The present studies indicate that no abnormal junction of PBS but stenosis of the distal common bile duct may be etiologically responsible for the choledochal cyst.