Chronic Hepatitis C: Pathological Anatomy

In infections with the hepatitis C virus (HCV), there is a wide spectrum of histological alterations that can affect the liver, from acute hepatitis to mild reactive phenomena to more severe forms, including chronic hepatitis with varying degrees of inflammation/fibrosis, cirrhosis, and hepatocellular carcinoma. In cases of acute hepatitis C, biopsies are rare, pathologists focusing their attention on the chronic form of the disease. The histological diagnosis of chronic hepatitis through liver biopsy remains extremely important in the management of patients infected with HCV, since it is the cornerstone of the detection of liver disease caused by the virus as well as the determination of the intensity of this disease. It should therefore be added to the diagnosis of infection made using serologic methods. The basic parameter for the histological diagnosis of chronic hepatitis is the presence of portal inflammatory infiltrate, with predominance of lymphocytes, usually with variations in the number of plasmocytes and histiocytes. This inflammation is accompanied by periportal activity of varying degrees (also denominated interface activity or piecemeal necrosis), parenchymal activity (lobular) and fibrosis. There are various classification systems using in the scoring and staging of chronic hepatitis [4,9,11,13,18,21,34]. Many of those systems are of historical importance. According to directive no. 863, issued by the São Paulo State Secretary of Health on November 4, 2002, it is recommended that one of two chronic hepatitis classification systems be used: the Sociedade Brasileira de Patologia (SBP, Brazilian Society of Pathology) system [13] or the METAVIR system [1,4]. These two systems are in fact very similar, and they both take into account the previously mentioned basic aspects of chronic hepatitis: periportal activity, lobular activity, and fibrosis. In addition to these, the classification system proposed by Ishak in 1995 [18] has been widely used in international literature. The Ishak system is an update of the system proposed by the same author in 1981, which gained popularity and was commonly referred to as the Knodell system [21] (a designation that should no longer be used), has been widely used in international literature. Table 1 shows an approximate correspondence between these systems, both for fibrosis (architectural alteration) and for periportal/lobular activity.