title: Steatosis of indeterminate cause in a pediatric group: is it a primary mitochondrial hepatopathy?
abstract: OBJECTIVE
  In children, hepatic steatosis may be related to inborn errors of metabolism (IEMs) or to non-alcoholic fatty liver disease (NAFLD). The aim of this study was to assess and characterize steatosis of indeterminate cause through morphological and morphometric analysis of liver tissue.
  
  
  METHODS
  Cross-sectional study at the Departments of Pathology of Faculdade de Ciências Médicas, Universidade Estadual de Campinas (FCM-Unicamp) and Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (FMB-Unesp).
  
  
  METHODS
  Eighteen consecutive liver biopsies obtained from 16 patients of ages ranging from 3 months to 12 years and nine months that were inserted in a database in the study period were analyzed using optical microscopy and transmission electron microscopy. Through electron microscopy, the mitochondrial density and mean mitochondrial surface area were determined in hepatocytes. Ten patients ranging in age from 1 to 14 years were used as a control group.
  
  
  RESULTS
  "Pure" steatosis was detected, unaccompanied by fibrosis or any other histological alteration. Microvesicular steatosis predominated, with a significant increase in mean mitochondrial surface area.
  
  
  CONCLUSIONS
  Microvesicular steatosis may be related to primary mitochondrial hepatopathy, especially due to reduction of β-oxidation or partial stagnation of oxidative phosphorylation. For these reasons, this form of steatosis (which should not be called "pure") is likely to represent an initial stage in the broad spectrum of NAFLD. We have drawn attention to cases of steatosis in the pediatric group, in which the microvesicular form predominates, since this may be associated with mitochondrial disorders.
authors.affiliation: Department of Pediatrics, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil. gustavohs@puc-campinas.edu.br
authors.forename: Gustavo Henrique
authors.initials: GH
authors.lastname: Silva
authors.forename: Gabriel
authors.initials: G
authors.lastname: Hessel
authors.forename: Kunie Iabiku Rabello
authors.initials: KI
authors.lastname: Coelho
authors.forename: Cecília Amélia Fazzio
authors.initials: CA
authors.lastname: Escanhoela
mesh_terms: D002648:Child; D002675:Child, Preschool; D022162:Cytoplasmic Vesicles / Q000145:classification / Q000473:pathology*; D003937:Diagnosis, Differential; D004812:Epidemiologic Methods; D005234:Fatty Liver / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008930:Mitochondria, Liver / Q000648:ultrastructure*; D028361:Mitochondrial Diseases / Q000473:pathology*; D065626:Non-alcoholic Fatty Liver Disease