title: Proposal for a histological scoring and grading system for non-alcoholic fatty liver disease.
abstract: OBJECTIVE
  The spectrum of histopathological features in non-alcoholic fatty liver disease (NAFLD) has been well described. At least two scoring systems have been established. We propose here a system in which numerical scores are obtained using the different features.
  
  
  METHODS
  Twenty-five cases of well-defined NAFLD were identified. Two pathologists blinded to identifiers and clinical data independently scored the liver biopsies twice for portal fibrosis (PF: 0-6), lobular inflammation and necrosis (LIN: 0-3), Mallory bodies (MB: 0-3), hepatocyte ballooning (HB: 0-3), perisinusoidal fibrosis (PSF: 0-3) and fatty change (FC: 1-4). The kappa statistic tested observer concordance. Non-parametric measures of correlation and hierarchical cluster analysis were used to elaborate a grading system.
  
  
  RESULTS
  A broad spectrum of NAFLD was observed. Intra- and interobserver concordance was satisfactory. An activity score was created (AS: 0-12) as the sum of LIN, MB, HB and PSF, but not FC. A system for severity of NAFLD was developed: Grade 1 (PF: 0-2 and AS: 0-4), Grade 2 (PF: 3 or AS: 5-7) and Grade 3 (PF: 4-6 or AS: 8-12). Diabetes, elevated alkaline phosphatase and decreased platelets were associated with advanced grade.
  
  
  CONCLUSIONS
  This simple, reproducible NAFLD score produces a three-tier severity grade. This numerical system may prove useful in assessing disease severity and interval changes.
authors.affiliation: Division of Gastrointestinal and Liver Diseases, Rancho Los Amigos Liver Unit, University of Southern California, 2011 Zonal Avenue, Los Angeles, CA 90033, USA. mendler@hsc.usc.edu
authors.forename: Michel Henry
authors.initials: MH
authors.lastname: Mendler
authors.forename: Gary
authors.initials: G
authors.lastname: Kanel
authors.forename: Sugantha
authors.initials: S
authors.lastname: Govindarajan
mesh_terms: D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D015331:Cohort Studies; D018450:Disease Progression; D005234:Fatty Liver / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008103:Liver Cirrhosis / Q000473:pathology* / Q000503:physiopathology; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011336:Probability; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index