Proposal for a histological scoring and grading system for non-alcoholic fatty liver disease.
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.
Mendler
Michel Henry
MH
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
Kanel
Gary
G
Govindarajan
Sugantha
S
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