Liver tissue examination.

Abstract

Histopathological study of the liver biopsy in viral hepatitis B allows to diagnose acute hepatitis, its severity and stage of evolution. Prediction of chronicity is feasible after two months. In chronic disease, histopathology allows to diagnose chronic hepatitis, its aetiology, grade of severity and stage of progression. Interface hepatitis and bridging confluent necrosis are important prognostic features. Severity is graded according to extent of necro-inflammatory lesions, which include portal inflammation, interface hepatitis, intralobular liver cell damage and death, and confluent (bridging) necrosis. Staging of progression is based on extent of fibrosis and lobular architectural changes (cirrhosis). Semiquantitative scoring of grade and stage is useful in trials of new drugs, in clinical research, and for comparison of preand post-treatment biopsies. It is not recommendable in routine diagnostic practice. In situ hybridization and (immuno-)electron microscopy are less practical and mostly used in research. Immunohistochemical staining for HBV antigens, especially for HBcAg and HBsAg, is useful for specifying the aetiology and the viral phase of the disease. The viral replicative phase is characterized by mild activity, nuclear localization of HBcAg, cytoplasmic HBeAg and membranous expression of HBsAg; the viral clearance phase features more severe inflammation and necrosis, possibly including the bridging type, whereas immunostaining reveals nuclear, cytoplasmic and membranous HBcAg; HBsAg stains in the cytoplasm of some cells, and in cellular membranes; the residual integration phase reveals no or only mild activity and cytoplasmic HBsAg, without demonstrable HBcAg. Attention for and reporting of premalignant lesions is important in improving adequate patient surveillance for possible development of hepatocellular carcinoma. Recognizable lesions include large cell and small cell liver cell dysplasia in dysplastic foci and nodules.