The microanatomy of the intrahepatic bile duct in polycystic disease: comparison of the cpk mouse and human.

The cpk mutation in mice produces a lethal recessive form of polycystic kidney disease (PKD) that, like human forms of the condition, is associated with an age-related incidence of hepatic cysts. Injection of plastic into the biliary tree of affected animals revealed that these cysts arise from focal dilatations of the epithelial lining that may enlarge to the point that they obstruct the bile ducts. This concept was supported by histological and scanning and electron microscopic studies. No evidence could be found of primary obstruction of the biliary tree. The same techniques were then employed in specimens of human liver from patients with both recessive (ARPKD) and dominantly inherited PKD (ADPKD). Similar abnormalities of the biliary tree were identified. These abnormalities were not found in control liver samples from patients without PKD. The liver of the patient with ADPKD also demonstrated many von Meyenburg complexes. These were related to some cyst development, but these complexes freely communicated with bile ducts, contrary to currently held opinion. We conclude that hepatic abnormalities in the cpk mouse and human PKD arise from changes in bile ducts that are analogous to the renal lesions.