Pancreaticobiliary maljunction without bile duct dilatation in children: distinction from choledochal cyst.

OBJECTIVES Pancreaticobiliary maljunction without bile duct dilatation (nondilated type) is rare in children, and its definition remains unclear. There is controversy over treatment between pediatric and adult patients. We reevaluated our previous definition of the nondilated type in children (common bile duct diameter <or=6 mm on cholangiography). PATIENTS AND METHODS Of 150 children with pancreaticobiliary maljunction, 14 fulfilled the definition of the nondilated type. Clinical and cholangiographic findings were reviewed and compared with cholangiograms of 17 children without biliary diseases (controls). The age-related normal range of the choledochal diameter was defined in combination with previous data. RESULTS All of the patients had symptoms and signs similar to those of choledochal cysts. Cholangiographic features of choledochal cysts were detected in all of the patients (dilated common channel, 8; distal bile duct stenosis, 5; dilated cystic duct, 4; filling defect in the common channel, 8). The choledochal diameter in control children increased with age. Only 4 patients (29%) had a choledochal caliber within the normal range. CONCLUSIONS Most pediatric cases reported as the nondilated type are slightly dilated (forme fruste) choledochal cysts and differ from the nondilated type seen in adults. The nondilated type in children should be defined on the basis of the age-related choledochal diameter.