A CASE OF HEPATIC FOCAL NODULAR HYPERPLASIA WITHOUT CENTRAL SCAR LOCALIZED IN THE LIVER OF THE BASE OF THE RIGHT HEPATIC VEIN

Abstract

A 19-year-old man was accidentally found to have a tumor of 2cm in diameter in the S₇ segment of the liver behind the base of the right hepatic vein by ultrasonography. He had no infection with hepatitis B or C virus, and his liver function, serum AFP and PIVKA-II levels were in normal values. A well-enhanced tumor was observed by computed tomography, magnetic resonance imaging, and angiography, however, there were no findings of central scar or spoke wheel appearance in the tumor. Partial resection of the liver was performed because it was difficult to differentiate from hepatocellular adenoma or hepatocellular carcinoma. Resected specimen showed that the tumor was 27mm in diameter and simple nodular type without capsule. Histopathological examination showed proliferation of hepatocytes without atypism, fibrosis and bile duct proliferation in the Glisson, but no central scar was seen in the tumor. Finally it was diagnosed as focal nodular hyperplasia (FNH).
Although the characteristic findings of FNH are central scar, spoke wheel appearance and the existence of Kupffer's cell, few cases have such typical findings and we have difficulties in differentiation from hepatocellular carcinoma. Thoracolaparotomy by the right oblique incision is the best approach for operating around the base of the right hepatic vein safely.