Liver biopsy is not necessary for diagnosis, but it is helpful for grading the severity of disease and staging the degree of fibrosis and permanent architectural damage. Hematoxylin and eosin stains and Masson’s trichrome stain are used to grade the amount of necrosis and inflammation and to stage the degree of fibrosis. Specific immunohistochemical stains for HCV have not been developed for routine use. Liver biopsy is also helpful in ruling out other causes of liver disease, such as alcoholic liver injury or iron overload.
HCV causes the following changes in liver tissue:
Necrosis and inflammation around the portal areas, so-called “piecemeal necrosis.”
Necrosis of hepatocytes and focal inflammation in the liver parenchyma.
Inflammatory cells in the portal areas (“portal inflammation”).
Fibrosis, with early stages being confined to the portal tracts, intermediate stages being expansion of the portal tracts and bridging between portal areas or to the central area, and late stages being frank cirrhosis characterized by architectural disruption of the liver with fibrosis and regeneration.
Grading and Staging of hepatitis by assigning scores for severity are helpful in managing patients with chronic hepatitis. The degree of inflammation and necrosis can be assessed as none, minimal, mild, moderate, or severe. The degree of fibrosis can be assessed similarly. Scoring systems are particularly helpful in clinical studies on chronic hepatitis.