Caroli first described a rare syndrome of communicating cavernous ectasia of the intrahepatic ducts in 1958. The syndrome is characterized by saccular dilatation of the intrahepatic bile ducts which may be generalized, limited to one segment of liver or may be associated with extrahepatic ductal dilatation. There is a high incidence of stone formation and cholangitis related to bile stasis. There is also a high association with various forms of renal cystic disease, most notably renal tubular ectasia (medullary sponge kidney) and possible cystic disease of the pancreas. There is absence of portal hypertension and cirrhosis. The renal tubular ectasia is relatively benign. Although associated with renal stones and infection, hypertension and renal failure are not seen.

Caroli's disease usually presents in children or young adults. Clinically, the presentation is one of recurrent pain and fever related to cholangitis and stone formation. The etiology of this condition is unknown. Some authors classify Caroli's disease as part of the spectrum of biliary cystic disease (see Choledochal Cyst) because of the occasional overlap of the features of choledochal cyst and hepatic fibrosis. The key feature is saccular dilatation of the ducts, not separate liver cysts. There is an increased incidence of carcinoma of the bile ducts in these patients.

The cholangiographic findings are characteristic in this disease - enlarged, saccular, fusiform intrahepatic ducts. Ducts in both lobes of the liver are usually involved; the extrahepatic ducts may be involved as well, as was seen in this case. US and CT reveal the branching tubular ducts with focal areas of ectasia and calculi, if present. A hepatobiliary scan may suggest the diagnosis by the unusual scintigraphic pattern of retained activity throughout the liver. PTC or ERCP are the procedures of choice to confirm the diagnosis and better delineate the anatomy by showing the direct communication of the ectatic areas with the biliary tree.