Pathology of hepatolithiasis associated with biliary malformation in Japan.

A national survey of the morphologic features of hepatolithiasis in Japan disclosed that 13 (4.8%) of the 273 cases examined were associated with obvious biliary malformations: Caroli's disease with congenital hepatic fibrosis (one case), adult polycystic disease of the liver and kidneys (one case), choledochal cyst (nine cases), and anomalous pancreaticobiliary ductal union (four cases). The latter two malformations overlapped in two cases. Intrahepatic calculi in all of these cases were of brown pigment stones, suggesting that focal bile stasis as well as bacterial infection might have played an important role in their formation and growth. It seems likely that such phenomena occur in the congenitally dilated segments of the intrahepatic biliary tree. These data imply that biliary malformation is one of the lithogenic factors in hepatolithiasis in Japan.