Non-alcoholic fatty liver disease: An expanded review

Table 2 Steatosis, activity, and fibrosis scoring system[91,124]

Steatosis score (S): Assessed the quantities of large or medium-sized lipid droplets (0-3)

S0: < 5%

S1: 5%-33%

S2: 34%-66%

S3: > 67%

Activity grade (0-4): Sum of scores for ballooning and lobular inflammation

A1: Mild activity

A2: Moderate activity

A3 and A4: Severe activity

Hepatocyte ballooning (0-2)

0: None

1: Foci of hepatocytes with rounded shape, pale or reticulated cytoplasm

2: Foci of hepatocytes with rounded shape, pale or reticulated cytoplasm and enlargement (> 2 × normal size)

Lobular inflammation (0-2)

0: None

1: < 2 foci per 20 × field

2: > 2 foci per 20 × field

Fibrosis stage (F)

F0: No relevant fibrosis

F1: 1a - mild zone 3 perisinusoidal fibrosis

1b - moderate zone 3 perisinusoidal fibrosis

1c - portal fibrosis

F2: Zone 3 perisinusoidal fibrosis with periportal fibrosis

F3: Bridging fibrosis

F4: Cirrhosis