A case of hepatic angiomyolipoma mimicking hepatocellular carcinoma

A 50-year-old woman with a liver mass on abdominal ultrasonography was referred for further evaluation. HBs antigen and HCV antibody were negative, but HBs antibody and HBc antibody were positive. Liver function tests were normal. A 24×15 mm low echoic mass was seen in segment 4 of the liver on ultrasonography. Enhanced sonography showed early enhancement with drainage via the hepatic vein. In the Kupffer phase, the tumor appeared as a defect. Abdominal enhanced CT and MRI demonstrated a high-density mass in the arterial phase and wash out in the portal phase. Based on these imaging findings and the possibility of occult HBV, we suspected hepatocellular carcinoma and a segment 4 resection was performed. Histopathologically, perivascular epithelioid cells and a few fat cells were seen. Immunohistochemically, HMB-45, MelanA and αSMA were positive. The tumor was diagnosed as a hepatic angiomyolipoma, which may be difficult to distinguish from hepatocellular carcinoma.