Histopathological evaluation of fatty and alcoholic liver diseases

Fatty liver disease (FLD) represents a common form of hepatic dysfunction among adults and children. Recognition of steatosis is usually straightforward but the differential diagnosis is broad. Macrovesicular steatosis may occur due to alcohol use or metabolic factors including obesity and hyperinsulinemia. Steatosis is, in some patients, accompanied by varying degrees of inflammation, ballooning hepatocyte degeneration or fibrosis, or both. The pathologist's recognition and interpretation of these features, when present, is critical for the classification and prognostication of the disease. Recent advances in the study of FLD have yielded new information for the surgical pathologist to guide the interpretation of steatosis in children and adults, and in patients with other forms of liver disease such as chronic viral hepatitis. This article details the current terminology for various forms of FLD, highlights the key histological features and reviews recent advances in the field.