[Congenital cystic diseases of the intra and extrahepatic bile ducts].

Congenital cystic lesions of bile ducts may affect intra or extrahepatic bile ducts. Intrahepatic lesions include five entities: congenital hepatic fibrosis, Caroli's syndrome, von Meyenburg complexes, simple cyst of the liver and polycystic liver disease. Congenital hepatic fibrosis and von Meyenburg complexes are secondary to ductal plate malformation affecting the smallest intrahepatic bile ducts. Cystic dilatations are of small size and only detected at histological examination of the liver. They have few clinical consequences. In congenital hepatic fibrosis, the main manifestations result from portal hypertension. Caroli's syndrome is secondary to ductal plate malformation affecting the largest intrahepatic bile ducts. Cystic dilatations are macroscopic and responsible for cholangitis and may lead to biliary stones and carcinoma which develop within cystic dilatations. Caroli's syndrome may be or not associated with congenital hepatic fibrosis. In case of associated congenital hepatic fibrosis, portal hypertension is present. Simple cyst of the liver and polycystic liver disease are characterized by cystic dilatations which, by contrast to the preceding entities, do not communicate with the rest of biliary tree. As a result, they have only few clinical consequences. In congenital hepatic fibrosis and polycystic liver disease, renal abnormalities are frequently observed. They correspond to renal malformations associated with biliary malformations. In congenital hepatic fibrosis, renal lesions are characterized by ectatic collecting tubules which are present in two thirds of the cases and transmitted as an autosomal recessive trait. In polycystic liver disease, renal lesions are characterized by polycystic disease which is present in half of the cases and transmitted as an autosomal dominant trait. Congenital cystic lesions of extrahepatic bile ducts consist of choledochal cyst, which is secondary to malformation of the pancreato-biliary ductal junction. The major risk of choledochal cyst is the development of intracystic cancer, the prevention of which is total surgical resection of the cyst.