Nonalcoholic fatty liver disease (NAFLD) is a common and increasingly recognized disorder characterized by the accumulation of macrovesicular fat in hepatocytes. The condition of hepatic steatosis in association with obesity in adults was reported nearly a half century ago but received little attention compared with fatty liver associated with chronic alcohol consumption [1]. Two decades later, in 1979, Adler and Schaffner [2] reported that liver histology in a group of 29 overweight adult patients was similar to the findings of alcoholic liver disease including cases with fatty liver, fatty hepatitis, fatty fibrosis, and fatty cirrhosis. However, it was 1 year later that the field of NAFLD was truly established when a group of astute physicians at the Mayo Clinic gave the name nonalcoholic steatohepatitis (NASH) to a “hitherto unnamed disease” [3]. They too recognized that many patients had liver disease that seemed similar to alcoholic liver disease despite a clear demonstration of strict abstinence. Shortly thereafter, three cases of NASH were reported in children [4]. Over the ensuing 2 decades, much progress has been made in understanding the epidemiology, clinical features, and histology of pediatric NAFLD. Efforts at treatment are still early but deserve special attention.

TERMINOLOGY

The terminology continues to be a source of confusion and controversy. The initial term, NASH, referred to patients who had sufficiently clinically relevant disease manifestations to come to the attention of a hepatologist.