Choledochal cysts.

Caroli disease (type V choledochal cyst)

Choledochal cysts are congenital conditions involving cystic dilatation of bile ducts.

Congenital liver abnormalities, such as Caroli's syndrome or choledochal cysts, have been associated with an approximately 15% lifetime risk of developing cholangiocarcinoma.

Congenital biliary cystic disease, such as choledochal cysts or Caroli's disease, has also been associated with malignant transformation in up to 25% of cases.

Choledochal cysts are treated by surgical excision of the cyst with the formation of a roux-en-Y anastomosis to the biliary duct.

Caroli disease is distinct from other diseases that cause ductal dilatation caused by obstruction, in that it is not one of the many choledochal cyst derivatives.

Bile duct cancer may occur more frequently in patients with a history of primary sclerosing cholangitis, chronic ulcerative colitis, choledochal cysts, or infections with the fluke, Clonorchis sinensis.