Autoimmune hepatitis-is histology conclusive?

Abstract

Liver biopsy is an essential and necessary element in the diagnosis and management of autoimmune hepatitis, and is of very special importance in the scoring system for diagnosis. Histopathology shows moderate to severe inflammatory infiltrates with abundant plasma cells in the enlarged portal tracts with interface hepatitis and moderate to severe necroinflammatory lesions in the lobules with lymphoplasmacytic reaction. Regeneration develops with rosette formation and regenerative nodules. One important issue is the differentiation between acute onset of autoimmune hepatitis and a flare up of chronic disease; this cannot be diagnosed in some cases clinically and therefore requires a biopsy to evaluate the stage of the disease. There are some variants of the disease with cholestatic features such as autoantibody negative autoimmune hepatitis and giant cell hepatitis as well as overlap syndromes with primary biliary cholangitis and primary sclerosing cholangitis. Clinically, three types of autoimmune hepatitis are differentiated according to autoantibody formation and the clinical picture, however, histopathologically there is no difference between these three types. Differential diagnosis of autoimmune hepatitis includes drug-induced liver injury with minocycline, alpha methyldopa, nitrofurantoin and checkpoint inhibitors such as infliximab. Wilson´s disease is also an important differential diagnosis especially in young adults. A liver biopsy is mandatory to confirm the diagnosis of autoimmune hepatitis but histopathology alone is not conclusive.

Keywords: Differential diagnosis of hepatitis; histopathology of the liver; immune mediated liver disease; liver cirrhosis; overlap syndromes.

Figure 1

Histopathologic features of autoimmune hepatitis. (A, hematoxylin and eosin) Enlarged, densely infiltrated portal tract with interface hepatitis. The infiltrate consists mainly of lymphoplasmacytic cells; there are many hepatocellular necroses (arrows) and emperipolesis with lymphocytes (circles). (B, chromotrope aniline blue) Fibrosis starts with formation of collagen fibers in the portal tracts as is shown by staining with chromotrope aniline blue. (C, hematoxylin and eosin) Focal necrosis in the lobule close to zone 3 with several clusters of plasma cells. (D, hematoxylin and eosin) Regeneration of parenchyma with rosetting of hepatocytes in the periportal area (circles).