Role of liver biopsy in nonalcoholic fatty liver disease

Table 1 Brunt grading system

Grade	Steatosis	Ballooning	Inflammation
Mild (1)	1-2 (< 66%)	Minimal	L: 1-2 P: 0-1
Moderate (2)	2-3	Present-zone 3	L: 2 P: 1-2
Severe (3)	2-3	Marked-zone 3	L: 3 P: 1-2

Reproduced with permission[101]. Steatosis: grade 1: < 33%; grade 2: > 33%-66%; grade 3: > 66%. Lobular inflammation: grade 1: < 2 foci per 200 × field; grade 2: 2-4 foci per 200 × field; grade 3: > 4 foci per 200 × field. Portal inflammation: grade 0: None; grade 1: Mild; grade 2: Moderate; grade 3: Severe. Ballooning: grade 1: Rare; grade 2: Prominent ballooning. L: Lobular/acinar inflammation; P: Portal inflammation.

Table 2 Brunt staging system

Stage	Zone 3 PSF, focal or extensive	Portal, periportal	Bridging	Cirrhosis
1	+	0	0	0
2	+	+	0	0
3	+/-	+/-	+	0
4	+/-	+/-	+/-	+

Reproduced with permission[101]. PSF: Perisinusoidal fibrosis.

Table 3 Nonalcoholic steatohepatitis clinical research network nonalcoholic fatty liver disease scoring system

Steatosis grade	Lobular inflammation	Liver cell ballooning
0: < 5%	0: No foci	0: None
1: 5%-33%	1: < 2 foci per 200 × field	1: Few ballooned hepatocytes
2: 34%-66%	2: 2-4 foci per 200 × field	2: Many ballooned hepatocytes
3: > 66%	3: > 4 foci per 200 × field

Reproduced with permission[65]. Nonalcoholic fatty liver disease activity score (NAS): Steatosis + inflammation + ballooning. Fibrosis, 0: None; 1: Perisinusoidal or periportal; 1A: Mild, zone 3 perisinusoidal; 1B: Moderate, zone 3 perisinusoidal; 1C: Portal, periportal; 2: Perisinusoidal and portal/periportal; 3: Bridging fibrosis; 4: Cirrhosis.