Liver biopsy interpretation in hepatitis. Part II: Histopathology and classification of acute and chronic viral hepatitis/differential diagnosis.

The morphological classification of acute and chronic viral hepatitis has been subject of considerable controversy. Main problems in nomenclature have arisen from the confusion of pathologically defined lesions with purely clinical designations. The classification used in this article is based on a number of recent reviews in which a certain measure of agreement has been reached between clinicians and histopathologists. As a general rule, in acute forms of hepatitis diffuse lobular changes predominate over portal lesions while chronic hepatitis is characterized by conspicuous alterations of portal (and periportal) areas. This report will merely summarize main diagnostic features of the different forms of viral hepatitis. For more detailed information the reader is referred to several leading articles discussing in detail morphology, and putting emphasis on pathogenesis. An exact "staging" of viral hepatitis by histologic criteria is an important tool in the evaluation of prognosis, indication and control of therapy as well as for comparison with immunologic findings.