Hepatocellular carcinoma and nonalcoholic steatohepatitis developing during long-term administration of valproic acid

We report a case of hepatocellular carcinoma (HCC) arising in nonalcoholic steatohepatitis (NASH). The patient, a 64-year-old man, was incidentally found to have multiple tumors in the liver when admitted for pneumonia. He had been obese, had been receiving a standard dose of valproic acid since clipping surgery for subarachnoid hemorrhage 17 years previously, and had not consumed any alcohol since the surgery. Laboratory data revealed moderate hyperlipidemia and no evidence of diabetes mellitus, hepatitis B or C infection. The patient died of hepatic insufficiency, and an autopsy was performed. A tumor, a maximum of 13 cm in diameter, grossly occupied the entire left lobe and one third of the right lobe of the liver. Histologically, moderately differentiated HCC was found with foci of poorly differentiated HCC. The non-tumorous area showed NASH with moderate bridging fibrosis, without interface hepatitis, hemochromatosis, or copper accumulation. In this patient, obesity, hyperlipidemia, and long-term treatment with valproic acid could have all been associated with induction of NASH. The present case suggests that HCC could develop in non-cirrhotic NASH liver, and that chronic inflammation in itself could be an important risk factor in the development of HCC.