Two cases of non-alcoholic steato-hepatitis developing from simple fatty liver

We describe two cases of non-alcoholic steatohepatitis (NASH) developing from simple fatty liver and detected by histological examination in two women. In both cases hypertension and diabetes mellitus showed no exacerbation during follow-up; hepatitis C antibody and hepatitis B surface antigen were negative; ultrasound (US) and computed tomography (CT) revealed fatty liver (moderate in one patient and severe in the other). Body mass index (BMI) was 48 and 44 in 2004 and 2007, respectively, in one and 24 in both 2006 and 2007, respectively, in the other. Liver function tests showed some fluctuation in aspartate aminotransferase and alanine aminotransferase. The first US-guided liver biopsy showed simple fatty liver; the second biopsy after two and a half years on one patient and one and a half years on the other, revealed histological features of NASH characterized by predominantly macrovesicular fatty change (40% in one and 80% in the other) with occasional ballooning, fibrosis (moderate in one and slight in the other) extending from zone 3 to zone 1, intraacinar inflammation with neutrophil infiltration, and mild portal chronic inflammation with piecemeal necrosis. Fibrosis progressed from stage 0 to stage 2 in two and a half years in one patient, and from stage 0 to stage 1 in one and a half years in the other. Clinicians should be vigilant during the clinical course of NASH developing from simple fatty liver.