Electron microscopic studies of the hepatic tissues biopsied at hepatic porto-enterostomy or porto-cholecystostomy were performed in 14 patients of biliary atresia. The intrahepatic bile ducts showed the evidences of degenerative changes in 11 out of 13 patients; abnormal increase or decrease in electron density of the cystoplasm and the nuclei, cytoplasmic accumulation of the electron dense materials, cytoplasmic vacuoles and disrupted cell membrans, cystic dilatation of the smooth surface endplasmic reticulum, and dilatation of the intercellular spaces. In many degenerative bile ducts their lumens were found to be narrowed by edematous projection of the cytoplasm (blebs) or by accumlation of the fragments of the degenerative epitherial cells and rarely by bile thrombi. The ductal lumens were not obstructed in patients who completely recovered from jaundice after hepatic porto-enterostomy or hepatic porto-cholecystostomy.
