Prevalence and nonspecificity of microvesicular fatty change in the liver

Hepatic microvesicular fat (MVF) has been associated with clinical syndromes of liver failure (such as acute fatty liver of pregnancy and Reye's syndrome). We performed this pilot study to investigate the specificity and potential risk factors of MVF. Sections of the liver from 17 adult autopsies were snap-frozen, and Oil Red O (ORO)-stained sections were obtained. The presence of MVF in the ORO stains was analyzed in a semiquantitative manner: 3+ = > 90% liver parenchyma with MVF; 2+ = 25-90%; 1+ = 1-24%. H&E-stained liver sections were reviewed independently to determine the presence and extent of inflammation, fibrosis, and necrosis. Autopsy reports were reviewed for the gross findings; medical records were reviewed for demographic data, medical history, and, in particular, medication usage. The study consisted of 10 males and 7 females (15 white, 2 black), with a median age of 76 years (range: 50-88). MVF was identified in 16 patients (94%); it was infrequent (1+, 2+) in the majority, but 4 patients (24%) had 3+ MVF. MVF was not associated with the age or sex of the patients, liver weight, postmortem interval to examination, or other histologic features in the liver. None of the patients, including those with 3+ MVF, had a history of liver disease. All 4 patients with extensive MVF were using salicylates, as opposed to 2 of 5 with 2+ MVF and 1 of 8 with 0 to 1+ MVF (P = 0.015). In this autopsy study, the prevalence of MVF was high, with 24% of patients having extensive MVF.(ABSTRACT TRUNCATED AT 250 WORDS)