Kasai portoenterostomy - new insights from hepatic morphology

Background/Purpose: The aim of this paper was to investigate the mechanism of long-term biliary drainage after Kasai portnenterostomy by clinicopathologic study of hepatic morphology in explanted livers. Methods: Explanted livers from 13 consecutive children undergoing transplantation for biliary atresia were examined in detail using a standardized protocol. Group 1 (n = 6) had no Kasai procedure before transplantation at a median age of 8 m. Group 2 (n =4) were transplanted at a median age of 10 m after a failed Kasai portoenterostomy. Group 3 (n = 3) had a successful Kasai but required transplantation for complications of chronic liver disease at 12-14 years. Pathology findings were correlated with hepatic morphology determined by pretransplant magnetic resonance imaging. Results: Large perihilar regenerative nodules (8-14 cm diameter) were observed in 2 patients after successful Kasai portoenterostomy, less well-defined perihilar nodules in group 2 patients, and no regenerative nodules in group 1. Microscopically, group I had diffuse biliary cirrhosis with evidence of progressive ductopenia during infancy. In group 2, perihilar regenerative nodules showed variable portal fibrosis but no cirrhosis and bile ducts were present with 68%-100% of hepatic arteries; in peripheral cirrhotic areas, bile ducts were absent in patients older than 9 in. The perihilar regenerative nodules in group 3 patients had a noncirrhotic architecture with preserved bile ducts, but the peripheral parenchyma was cirrhotic-, one patient had diffuse macronodular cirrhosis. These morphologic findings correlated well with magnetic resonance images, highlighting the preservation of relatively normal perihilar liver architecture after successful Kasai portoenterostomy. Conclusions: Urroperated biliary atresia is associated with progressive intrahepatic ductopenia leading to diffuse biliary cirrhosis. Kasai portoenterostomy can result in the growth of large perihilar regenerative nodules, probably as a consequence of surviving intrahepatic ducts in this region. In some patients, longterm success after Kasai portoenterostomy may depend on hyperplasia of the perihilar liver. (C) 2005 Elsevier Inc. All rights reserved.