Alcohol can induce a wide spectrum of histological changes in the liver. Three morphologic patterns of alcoholic liver injury are now generally accepted, i. e. fatty change, alcoholic hepatitis and alcoholic cirrhosis, but a broad array of lesions has been added to this list in recent years. These damage patterns differ considerably in their significance as to indication and diagnostic power of liver biopsies. Liver biopsy is recommended in patients with clinically suspected alcoholic liver disease for diagnostic and prognostic reasons. Moreover, clinicians want to exclude nonalcoholic liver diseases that might otherwise be missed. Alcoholic hepatitis, which is associated with increased morbidity and mortality, has the highest degree of diagnostic specificity in biopsies, because its features are well-defined and are mimicked by a rather small group of other causes. When associated with perivenular and pericellular fibrosis, it may provide prognostic parameters. In contrast, fatty liver, which may be induced by alcohol as well as other etiologies, usually does not need liver biopsy, with some exceptions. It may lead to cholestasis severe enough to mimic obstructive jaundice, or may result in abnormal imaging studies suggesting metastases. Verification of histological findings may be important when these circumstances arise. Cirrhosis is easily verified in biopsies of appropriate quality; however, advanced cirrhosis is a morphologically non-specific alteration, because cirrhotic tissue patterns converge irrespective, of their cause. Liver biopsy may help to identify nonalcoholic liver disease in patients suspected of harboring alcoholic liver disease. In fact, up to 20 % of biopsies may show other, potentially treatable disorders, thus extending the indication for liver biopsy in situations of complex clinical and laboratory patterns.
