Caroli Disease

Caroli disease is characterized by a congenital dilatation of the larger (segmental) intrahepatic bile ducts. Caroli described two varieties &: a pure form (Caroli disease), characterized by ectasias of the intrahepatic bile ducts without further histological abnormalities, and a combined form (Caroli syndrome) in which Caroli disease is associated with periportal fibrosis, with an histological picture resembling congenital hepatic fibrosis. Both varieties are associated with renal abnormalities corresponding to autosomal recessive polycystic kidney disease, and both are inherited in an autosomal recessive manner. Similarly to congenital hepatic fibrosis, Caroli syndrome has been reported in association with the adult type of polycystic disease or with choledochal cyst &. Variation in anatomic patterns have been described, as well as variations in the clinical picture. In Caroli disease the abnormality consists in moniliform or saccular dilatations of the larger intrahepatic bile ducts, with predominant involvement of the segmental ducts &. The dilated parts are in continuity with the rest of the biliary system and hence contain bile. The saccular dilatations of the ducts lead to stagnation of the bile and, in this way, predispose to biliary sludge formation and intraductal lithiasis, often complicated by superinfection. Duct anomalies predispose to cholangitis, often complicated by septicemia. Further complications include amyloidosis and cholangiocarcinoma. The incidence of biliary carcinoma is up to 100 times higher than in the normal population &.
In patients with Caroli syndrome, the clinical picture may be a combination of both Caroli disease and congenital hepatic fibrosis, cholangitis  and portal hypertension. The pathogenesis of Caroli disease seems to involve a total or partial arrest of remodeling of the ductal plate of the larger intrahepatic bile duct. In the Caroli syndrome, the hereditary factors causing the partial or complete arrest in remodeling of the ductal plates appear to exert influence, not only during the early period of bile duct embryogenesis, when larger ducts are formed, but also later during the development of more peripheral biliary ramifications (the interlobular bile ducts), thus resulting in the development of the characteristic lesions of congenital hepatic fibrosis.
As for congenital hepatic fibrosis, liver transplantation is indicated for chronic cholangitis with progressive hepatic failure, and for the high risk of cholangiocarcinoma development.