[Chronic hepatitis].

Chronic hepatitis is defined as primary necroinflammatory liver disease with a duration of at least 6 months. It is etiologically heterogeneous and may be caused by hepatitis viruses (B, C, D, others?), autoimmune processes, drug reactions and metabolic disorders. A certain percentage of chronic hepatitides is etiologically still uncertain (cryptogenic). Nomenclature and classification of chronic hepatitis proposed in 1968 on the basis of morphologic appearance is still widely used. However, in view of the recent advances in our knowledge of etiology, pathogenesis, course of the disease, and, particularly, progress in therapy a classification based on morphology alone is unsatisfactory. A modern classification of chronic hepatitis should be easy to apply and reproducible, and based on etiology, grading of necro-inflammation and staging of the disease. Grading should consider portal, periportal and lobular inflammation and type and extent of liver cell alterations and necrosis. Fibrosis and cirrhosis are histological features of staging. Alterations may be semi-quantified particularly to facilitate comparison of results in clinical trials.