In order to see if the term of "plasma cell hepatitis", dating back to the early sixties, is still valid as a morphological diagnosis for autoimmune chronic hepatitis (AICH), and to find out if the existence of several subgroups is reflected by histopathology, we investigated 26 patients with chronic hepatitis, who met the criteria of autoimmune hepatitis based on tests for antinuclear, anti-smooth muscle antibodies (SMA) and on immunoassays for liver-kidney-microsomal (LKM) antigen, liver membrane antigen (LMA), and soluble liver antigen (SLA). In our material autoimmune hepatitis represent the entire spectrum of chronic hepatitis with variable inflammatory activity ranging from chronic persistent hepatitis to severe inflammatory lesions in chronic active hepatitis with transition to cirrhosis. When compared to viral chronic hepatitis A and non-A, non-B, however, characteristic features can be evaluated consisting in broad hypocellular areas of collapse and microacinar transformation of hepatocytes with hydropic swelling being the predominant type of cell lesion. Eosinophilic clumping and acidophilic necrosis were insignificant. Plasma cells were not a constituent feature of AICH. From this histopathologic pattern it may be concluded that the disease seems to run a sluggish course in most patients, however, in few cases a dramatic development may determine the disease with fatal acute episodes which are terminated by death or fade into slow progression. The different subgroups could not be distinguished by histopathology.(ABSTRACT TRUNCATED AT 250 WORDS)