To investigate whether liver diseases other than autoimmune hepatitis (AIH) can present with the typical features of AIH, and to determine the impact of liver biopsy for differentiating AIH from these conditions.

The study used data collected at Hacettepe university hospital and numune education and research hospital from 2007 to 2011. The clinical, laboratory and histological findings of patients diagnosed with non-alcoholic steatohepatitis, drug-induced liver injury, primary biliary cirrhosis, primary sclerosing cholangitis, hemochromatosis and Wilson’s disease were evaluated to identify those who presented with the typical features of AIH, but had no liver histology compatible with or suggestive of AIH.

A total of 386 patients were evaluated, and four patients with typical features of AIH were identified. Three patients were positive for antinuclear antibodies, and one was positive for smooth muscle antibodies. Also, all four had increased levels of immunoglobulin G, and aminotransferase levels that were five times above the upper limit. According to simplified AIH criteria, all patients had a score of 6, indicating probable AIH. On liver biopsy, two patients were diagnosed with non-alcoholic steatohepatitis, another with drug-induced liver injury and a further one with primary biliary cirrhosis.

Liver diseases other than AIH can present with the typical laboratory features of AIH and, without liver biopsy, it is difficult to distinguish AIH than these conditions. Although histological findings have little impact on patients’ management and outcomes, for a definitive diagnosis of AIH, liver biopsy is essential and should be performed in all patients in whom it is suitable and not contraindicated.