Viral chronic moderate hepatitis
Chronic hepatitis is characterized by hepatic necroinflammation (chronic inflammatory infiltrate and necrosis of hepatocytes), fibrosis and biochemical disorders lasting for more than 6 months. According to necroinflammatory activity, chronic hepatitis may be mild, moderate or severe. The stage of fibrosis depends on its localization and degree of extension (absent, limited to portal tract without fibrous septa, complete or incomplete porto-portal fibrous septa and cirrhosis).
The main cause chronic hepatitis is viral infection : hepatitis B virus, hepatitis C virus, and others. Untreated, chronic viral hepatitis evolves into cirrhosis and hepatocellular carcinoma.
In moderate chronic hepatitis, the liver architecture is preserved, but portal tracts are enlarged (losing the normal triangular shape), with abundant chronic inflammatory infiltrate (lymphocytes, plasma cells, macrophages). Limiting plate of hepatocytes (which separates the portal tract from lobule) is interrupted (foci of hepatocyte necrosis surrounded by lymphocytes - piecemeal necrosis or interface hepatitis). This is followed by extension of inflammation into the periportal parenchyma. At this level, hepatocytes present hydropic change and/or fatty change. (H&E, ob. x20)
Chronic viral hepatitis. Portal tract with areas of interface hepatitis (piecemeal necrosis) : destruction of limiting plate of hepatocytes by infiltrating lymphocytes. (H&E, ob. x40)