A case of idiopathic fatty liver detectable only by ultrasonography.

A 40-year-old man was diagnosed as fatty liver according to our ultrasonographical criteria for fatty liver, i.e., liver-kidney contrast in the ultrasound mass screening of the liver, biliary tract and pancreas. He lacked any signs or symptoms, nor any known causes of fatty liver, i.e., obesity, diabetes, hyperlipidemia, ingestion of alcohol or drugs. Liver biopsy of this patient revealed fatty change of about 50% of the hepatic lobules. It has been difficult to suspect the presence of latent fatty liver which lacked both the abnormality in the liver function test and hepatomegaly, and even impossible when it lacked any risk factors. In the future as the ultrasonography becomes more generally used as a primary screening examination, "idiopathic latent fatty liver", like this patient, will be more frequently found and this, in turn, will contribute to the progress of the epidemiology and etiology of fatty liver.