Nonalcoholic fatty liver disease (NAFLD) is classified as nonalcoholic steatohepatitis (NASH) or simple steatosis (SS) according to histological findings. It is well recognized that NASH may develop into cirrhosis and hepatocellular carcinoma (HCC), both with unfavorable prognoses. Although the outlook of SS is reported to be better than that of NASH, the long-term prognosis of SS remains unclear. Here, we report the case of a patient who was diagnosed as having SS by a first liver biopsy, and later developed into cirrhosis and HCC over a period of 27 years. In 1980, a 42-year-old Japanese man was admitted because of abnormal liver function tests. He had no history of alcohol intake and was negative for hepatitis virus markers and autoantibodies. A liver biopsy specimen showed macrovesicular steatosis without ballooned hepatocytes, Mallory hyaline, lobular inflammation, or perisinusoidal/perivenular fibrosis, confirming the diagnosis of SS. The patient's serum aminotransferase levels did not normalize despite repeated dietary instruction, and in 2001, liver histology demonstrated cirrhosis with mild steatosis and hepatocyte ballooning, leading to the diagnosis of NASH-related cirrhosis. HCC appeared in 2007. Overall, this patient progressed to cirrhosis and HCC in 20 and 27 years, respectively, following initial diagnosis. Platelet counts and degree of steatosis, as assessed by periodic ultrasonography, were seen to gradually reduce with progression of fibrosis. This case demonstrates that even a diagnosis of SS does not guarantee non-progression to cirrhosis and HCC, and careful follow-up is needed not only in patients with NASH, but also in those with SS.
Keywords: Hepatocellular carcinoma; Hyaluronic acid; Liver cirrhosis; Simple steatosis.