A case of hepatocellular carcinoma arising from the intraductal hepatic bile duct without parenchymal lesion.

Abstract

Hepatocellular carcinoma (HCC) rarely presents as an intraductal tumor with no parenchymal lesions. Here, we present a case of HCC arising from an intrahepatic bile duct. A 74-year-old man who had been treated with direct-acting antiviral therapy for hepatitis C virus infection was referred to our hospital because of elevated serum prothrombin levels induced by vitamin K absence II (PIVKA-II). Initial imaging revealed no findings suspicious of HCC; however, repeat CT six months later revealed dilation of the intrahepatic bile ducts in the lateral segment of the liver. Cholangiography revealed a significant stricture of B3, and biopsy suggested adenocarcinoma. A left hepatectomy was performed with a preoperative diagnosis of intrahepatic cholangiocarcinoma. Although a surface nodule on the lateral segment of the liver, suspicious for intrahepatic metastasis, was found intraoperatively, radical resection was performed. Histopathological examination revealed a tumor filling the intrahepatic bile duct from the stump to the peripheral bile duct, with no infiltration into the liver parenchyma. The surface nodule is a dilated peripheral bile duct filled with a tumor with no extrabiliary invasion. Immunohistochemistry suggested HCC. No tumor lesions were observed in the hepatic parenchyma, and the tumor was finally diagnosed as HCC stemming from the biliary epithelium.