Newly Formed Hepatic Masses in Children with Biliary Atresia after Kasai Hepatic Portoenterostomy

Background: This report describes the clinicopathologic findings of six hepatic masses that developed after Kasai hepatic portoenterostomy (HPE) in six patients with longstanding biliary atresia (BA). Methods: Hepatic masses were found in six of 55 pediatric patients who underwent liver transplantation for BA after Kasai HPE from 1997 to 2009. Clinicopathologic analysis was performed and immunohistochemical staining was carried out for CD34, smooth muscle actin (SMA) and cytokeratin 7. Results: Of the six hepatic masses, two were diagnosed as focal nodular hyperplasia (FNH)-like lesions, two were large regenerative nodules (LRN), one was a mesenchymal hamartoma (MH) and one was a cholangiocarcinoma. The immunohistochemical staining findings for SMA and CD34 were more prominent for the FNH-like nodules than for the cirrhotic background liver. Dysplastic biliary epithelium arising from intestinal metaplasia was found in the cholangiocarcinoma. Conclusions: Our findings suggest that FNH-like lesions, LRNs and MH are the results of vascular hemodynamic changes after Kasai HPE and that cholangiocarcinoma is due to recurrent cholangitis after BA. All the lesions in this series must be included in the differential diagnosis of a newly formed hepatic mass in patients after portoenterostomy.