Fibropolycystic liver disease: CT and MR imaging findings.

Fibropolycystic liver disease encompasses a spectrum of related lesions of the liver and biliary tract that are caused by abnormal embryologic development of the ductal plates. These lesions (congenital hepatic fibrosis, biliary hamartomas, autosomal dominant polycystic disease, Caroli disease, choledochal cysts) can be clinically silent or can cause signs and symptoms such as cholangitis, portal hypertension, gastrointestinal bleeding, infections, and space-occupying masses. The different types of fibropolycystic liver disease demonstrate characteristic findings at computed tomography (CT) and magnetic resonance (MR) imaging. Patients with congenital hepatic fibrosis typically have imaging evidence of liver morphologic abnormalities, varices, splenomegaly, renal lesions, and other associated ductal plate abnormalities. Biliary hamartomas usually manifest as multiple cysts that are nearly uniform in size and measure up to 15 mm in diameter. Autosomal dominant polycystic disease typically manifests as an enlarged and diffusely cystic liver. In Caroli disease, cystic or fusiform dilatation of the intrahepatic ducts is seen, as well as the "central dot sign," which corresponds to a portal vein branch protruding into the lumen of a dilated bile duct. Choledochal cyst manifests as a fusiform or cystic dilatation of the extrahepatic bile duct. Awareness of these CT and MR imaging features is essential in detecting and differentiating between various fibropolycystic liver diseases and can assist in proper management.