Current anatomico-pathological classification of hepatitis: characteristics of HCV infection.

Better knowledge of the natural history and aetiology of chronic hepatitis and the introduction of effective treatments have lead to revising the histopathological classification of chronic hepatitis. The basic lesions observed in chronic hepatitis are intra-portal inflammatory infiltrate, piecemeal necrosis, lobular necrotico-inflammatory lesions, and fibrosis. The histological activity of chronic hepatitis is usually assessed by apply Knodell's score or histological activity index (HAI). This score includes inflammatory lesions and fibrosis. But fibrosis is in fact the consequence of portal and lobular inflammation. The current classifications, including that proposed at the 1994 world conference on gastroenterology, propose discriminating between activity, or grade, and fibrosis, or stage. The classification of chronic hepatitis has also been revised because it was ill-adapted to assessing the C virus-linked chronic hepatitis. Histologically, these are little active chronic hepatitis associated with intra-sinusoidal inflammatory infiltrates of the leukaemia type, intralobular microgranulomas, intraportal lymphoid aggregates, and lesions of the small biliary tracts. Although non-specific, these lesions are evocative enough to histologically back-up diagnosis. Liver biopsy confirms chronic hepatitis diagnosis, determines its grade and stage, sometimes its cause. Liver biopsy also permits assessing treatment response.