Congenital biliary dilatation may consist of 2 disease entities.

BACKGROUND/PURPOSE: This study aims to establish the possible mechanisms of pathogenesis of congenital biliary dilatation and to classify the disease accordingly.

METHODS

Radiologic features of congenital biliary dilatation and pancreaticobiliary malunion in 107 affected children were examined and correlated with laboratory results. Relative lengths/diameters were calculated to provide comparison between children of different ages. Intraluminal pressures of common bile duct (CBD) were measured intraoperatively.

RESULTS

The minimal relative diameters of distal CBD negatively correlated with the maximal relative diameters/lengths of dilated CBD, the maximal relative diameters of common hepatic duct, and left/right hepatic ducts. The intraluminal pressure in patients with a stenotic distal CBD (stenotic group) was significantly higher than that in patients with a nonstenotic distal CBD (nonstenotic group). The narrower the distal CBD, the more deranged the liver function. Conversely, serum/bile amylase levels were more elevated in the nonstenotic group. Common channel protein plugs were only found in the nonstenotic group, whereas common hepatic duct strictures, intrahepatic duct dilatations, and calculi were detected more frequently in the stenotic group.

CONCLUSION

We propose to categorize congenital biliary dilatation into 2 subgroups: (1) cystic type with stenotic distal CBD associated with deranged liver function and common hepatic duct stricture and (2) fusiform type with nonstenotic distal CBD associated with pancreatitis and common channel protein plugs. Different underlying pathologies of each group require different operative strategies.