Caroli's disease

(Jacques Caroli, born 1902, French physician), also called congenital dilatation of intrahepatic bile ducts or ductular ectasia, a cystic dilatation of the major intrahepatic bile ducts. Carolis disease is part of a spectrum, which includes congenital hepatic fibrosis and choledochal cysts and is associated with both. The cystic dilatation is lined with cuboidal epithelium and is in continuity with the branches of the main intrahepatic bile ducts.

The dilatation usually involves the entire liver, but cases limited to one segment or one lobe have been reported. In the "simple" type of congenital ductular ectasia the periportal fibrosis or inflammatory reaction is very limited, whereas in congenital hepatic fibrosis with ductular ectasia periportal fibrosis may be a prominent feature. This more common type of Carolis disease can be associated with cystic disease or tubular ectasia of the kidney. Clinical symptoms include fever and pain, stone formation in the intrahepatic ducts, cholangitis and liver abscess.

Plain radiography of the abdomen may very rarely reveal small intrahepatic bile duct calcifications. Cholangiography is best suited to depict the multiple ductal dilatation, called the "lollipop tree" aspect.

Findings on ultrasound include saccular or tubular dilatation of intrahepatic bile ducts, intraluminal bulbar protrusions, bridge formation across dilated bile ducts resembling internal septa within the dilated bile ducts and portal radicles partially or completely surrounded by dilated bile ducts. (Fig.1) These portal radicles if seen in axial projection appear as tiny, hyperechogenic structures centrally in the dilated bile duct and have been named: "central dot" sign. It is important to demonstrate the communication between the cystic ductal dilatation and the bile duct system either by cholangiography or by ultrasound in order to distinguish Carolis disease from polycystic liver disease or multiple simple hepatic cysts.

On CT Carolis disease is revealed by the presence of multiple, branching, round or tubular structures with fluid density which extend into the periphery of the liver. Higher density small structures within the dilated ducts represent noncalcified or calcified stones. Contrast-enhanced CT may demonstrate central enhancing tiny dots within the ductal dilatation, representing the intraluminal portal venous radicles.

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