Liver biopsy is one of the standard tests performed during the clinical evaluation of many patients suspected of having a liver disease, as well those who have a documented liver disease that needs to be monitored for its progression or its response to treatment. The main function of the liver biopsy is to stage (assess the extent of fibrosis or scarring of the liver) and to grade disease (quantify the extent and type of liver injury present). Accordingly the main reasons for performing the liver biopsy include the following:

Best results are obtained when the clinical hepatologist is performing it with well-defined questions in mind and following the evidence based indications, as listed in Table 1.

In a position paper prepared for the by American Association for the Study of Liver Diseases (AASLD) Rockey et al. (2009) indicate that the liver biopsy has three major roles:

We recommend this paper as an excellent guide for clinicians contemplating liver biopsy, primarily because it was written by a Practice Guidelines Committee including clinical hepatologists and pathologists. Furthermore its 34 recommendations are evidence based and numerically graded using the established criteria: Class (benefit versus risk, on a scale from I-the highest, to IV lowest usefulness effectiveness) and Level (strength of certainty, on a scale from A, highest to C, lowest of evidence).

The principal messages of that practice oriented position paper are worth reviewing further since they are important for understanding of the clinical value of the pathology findings in liver biopsies.

∎ Diagnostic value of liver biopsies. Historically, liver biopsy was considered to be the ultimate diagnostic approach to most liver diseases. Today we know that the biopsy findings are rarely diagnostic and should always be considered in context of other clinical and laboratory findings. It is important to remember that the biopsy data and their interpretation have their inherent value and also defined limitations. For example, certain typical morphologic aspects of liver diseases, such as florid duct lesion or granulomas of primary biliary cirrhosis, or steatosis and pericellular fibrosis in steatohepatitis cannot be recognized by any other means except biopsy. Liver biopsy is especially helpful in patients whose disease presents with atypical clinical manifestations, and those who have more than one or even more coexistent diseases. However, even these findings attain their full meaning only in conjunction with other findings.

Liver biopsy is often indicated in patients whose diseases present a diagnostic challenge or dilemma, systemic diseases also involving the liver, or diseases associated with abnormal liver function tests. Liver biopsy is also performed to confirm or eliminate a hypothetical diagnosis and in a search for the cause of a disease of unknown etiology. Acute liver failure, hepatomegaly and liver diseases associated with portal hypertension may have many causes and the liver biopsy could be helpful in defining the true nature of these conditions.

∎ Prognostic value. The most important prognostic findings in the liver biopsies include the extent and distribution of fibrosis inside the liver parenchyma. Obviously the extent of fibrosis can be assessed only by liver biopsy. These findings are most important in patients with HCV infection, steatohepatitis, primary biliary cirrhosis, autoimmune hepatitis, and primary sclerosing cholangitis. The extent of fatty change, iron, and copper accumulation are also important and best accomplished by tissue analysis.