Caroli's disease in congenital hepatic fibrosis and infantile polycystic disease.

Two of three patients with infantile polycystic disease and all three patients with congenital hepatic fibrosis revealed multiple gross cystic dilatation of the intrahepatic biliary tree, referred to as Caroli's disease. All three patients with congenital hepatic fibrosis showed recurrent cholangitis related to coexisting Caroli's disease, and two of them died of sepsis following cholangitis. There were several common morphologic findings in the intrahepatic biliary tree of macroscopic and microscopic levels in infantile polycystic disease and congenital hepatic fibrosis with Caroli's disease: 1. irregular, non-obstructive dilatation of the duct lumen; 2. bulbar protrusion of the duct wall into the lumen; and 3. bridge formation of the duct wall across the lumen. These ductal changes might be caused by a combination of uneven and disproportionate overgrowth of biliary epithelia and their supporting connective tissue. This pathogenetic mechanism might be operative along the entire intrahepatic biliary system in this disease group, and involvement of the smaller levels in early life might result in infantile polycystic disease and congenital hepatic fibrosis and simultaneous or possibly later involvement of the larger levels in Caroli's disease.