Cystic disease of the biliary tract.

Cystic disease of the biliary tract is rare in Western countries with an incidence of 1/2,000,000 live births. Five anatomical types are recognized. The majority (80%) become symptomatic before the age of 30 years. The cysts rarely have an intact epithelial lining and this often exhibits metaplasia. The risk of cancer developing in a choledochal cyst has been variously estimated at 2.5-28%. Malignancy is often associated with an abnormal pancreaticobiliary junction. Surgical treatment is indicated for types I-IV and is by excision rather than drainage. The treatment of Type V is difficult and should be conservative in the first instance. However, patients with severe symptomatic diffuse hepatic disease and progressive deterioration of liver function are best managed by hepatic transplantation.