Steatosis up to 66%, occasional ballooned hepatocyte (mainly zone 3), scattered intra-acinar neutrophils ± lymphocytes, no or mild portal inflammation
Grade 2 (moderate)
Steatosis of any degree, obvious zone 3 ballooning degeneration, intra-acinar neutrophils, zone 3 perisinusoidal fibrosis may be present, mild to moderate, portal and intra-acinar inflammation
Grade 3 (severe)
Pan-acinar steatosis, widespread ballooning, intra-acinar inflammation, neutrophils associated with ballooned hepatocytes, mild to moderate portal inflammation
Staging NAFLD
(1) Stage 1
Zone 3 perisinusoidal/pericellular fibrosis; focally or extensively present
(2) Stage 2
Zone 3 perisinusoidal/pericellular fibrosis with focal or extensive periportal fibrosis
(3) Stage 3
Zone 3 perisinusoidal/pericellular fibrosis and portal fibrosis with focal or extensive bridging fibrosis
