Pathology of viral hepatitis and its sequelae.

THANKS to liver biopsy and the frequency of viral hepatitis, the morphology of the disease has become so well known that there are only a few questions which remain open for discussion. The significance of certain histological features for the stage and prognosis of the disease seems still to be of interest. Most of these questions have been reviewed by our group, which belongs to the European Association for the Study of the Liver.2 The main cellular and architectural changes of viral hepatitis are of three types: i) liver-cell damage and inflammation in the lobule, 2) changes in architecture due to loss of hepatic cells, and 3) inflammation and the proliferation of mesenchymal cells and bile ducts in the portal tracts. These morphological alterations are summarized in Table I. Liver-cell damage and inflammation are the most constant characteristics of acute viral hepatitis. However, the same changes can be found in patients with prolonged hepatitis, with recurrent attacks of clinically acute hepatitis, or with chronic hepatitis and cirrhosis. We use the term confluent (submassive) where necrosis has affected substantial groups of adjacent liver cells with or without destruction of the greater part of the lobule, whereas focal necrosis describes the death of smaller groups of cells. Confluent necrosis may correspond to lobular zones (e.g., centrilobular necrosis) or it may occur in other patterns. It is not unusual for confluent necrosis to extend from centrilobular areas to portal tracts. The collapse of the necrotic zone then leads to the formation of a septum of connective tissue in the same location (Figure i).6 Such a septum is passive in the sense that it is formed by the condensation of pre-existing reticulin fibers rather than