Biliary Atresia: histopathologic observations and reflections upon its natural history.

Operative liver biopsies and specimens of the extrahepatic ducts and porta hepatis have been studied in 12 cases of biliary atresia. In all cases, the liver showed giant cell transformation and inflammation with mononuclear cells and neutrophils. Most had other features of neonatal hepatitis, including necrosis of hepatocytes. In the intrahepatic bile ducts of all cases but one, the hepatic ducts and glands at the porta hepatis, and in the extrahepatic ducts where epithelium remained, there was degeneration of the epithelium and intramural inflammation. In the ducts at the porta hepatis and in 6 of 8 extrahepatic ducts where epithelium remained, there was extensive mural fibrosis compromising the diameter of the duct lumens. Three cases showed the inflammatory changes distal to sites of closure of the extrahepatic ducts. These findings demonstrate that in biliary atresia, hepatitis, intrahepatic cholangitis, and sclerosing cholangitis of the extrahepatic ducts all interact to produce acquired obstruction to bile flow.