Adult giant cell hepatitis (AGCH) is a rare event and only about 100 cases have been reported within the last 20 years. The AGCH has been observed in association with viral infection, drug reactions or autoimmune disorders but in many cases its etiology remains unclear. AGCH manifests clinically as severe form of hepatitis histologically characterized by diffuse giant cell transformation of hepatocytes. We report the case of a 39-yr-old man with acute community-acquired hepatitis without previous pathology of the liver. Laboratory data revealed slight hypergammaglobulinemia and high titer of anti-smooth-muscle antibody with negative serology of hepatotropic viruses and absence of other known causes of hepatitis. Preliminary diagnosis of autoimmune hepatitis was established, additionally confirmed by excellent clinical and biochemical improvement during corticosteroid treatment. A liver biopsy showed the typical findings of panlobular syncytial giant cell hepatitis and positive HCV-RNA both in serum and liver. The above verified the diagnosis of acute type C hepatitis manifested histologically as adult giant cell hepatitis. After three months of treatment we withdrew corticosteroids as spontaneous clearance of HCV occurred and the lack of autoantibodies in serum as well as significant improvement of liver histology was ascertained. Within 30 months of the follow-up we have not observed biochemical and immunological abnormalities and control liver biopsy has shown no signs of hepatitis.

Keywords: adult giant-cell hepatitis, acute hepatitis C, autoimmune hepatitis