[Histopathologic study of the extrahepatic biliary system in uncorrectable congenital biliary atresia: its...

Histopathologic study was carried out on specimen of extrahepatic biliary system in 23 patients with congenital biliary atresia, and the data were compared with those obtained from a control group of 43 autopsy cases of newborns and infants. In the control cases, accessory tubulo-alveolar glands were observed around the extrahepatic bile duct, and in addition some small ductules were observed in the area of the porta hepatis. In cases of biliary atresia, characteristic findings were histologically detected at each level of the extrahepatic biliary system. In the area of the porta hepatis, there were many epithelial luminal structures in fibrous tissue with inflammatory infiltrates. Near the confluence, the bile duct completely disappeared to be replaced by fibrosis, and in the area between the porta hepatis and the confluence, granulation tissue surrounded by fibrosis was observed. The epithelial luminal structures in the area of the porta hepatis were thought to originate from the bile duct, draining ductules and accessory glands observed in the normal controls. These structures tended to decrease in number with time. In cases possessing a patent common bile duct, the gallbladder showed many mucous glands and no inflammatory changes. On the other hand, in cases with an obliterated common bile duct, the gallbladder showed chronic atrophic cholecystitis without any mucous glands. The pathogenesis remains unknown, but it is thought that this disorder results from non-infectious inflammatory changes initiated near the confluence of the normally developed bile duct.