Increased number of mesangial cells per unit of mesangium (traditionally more than 3 cells)
(i) M0: <50% of glomeruli showing mesangial hypercellularity (ii) M1: >50% of glomeruli showing mesangial hypercellularity
Endocapillary hypercellularity (E)
An increased number of cells within glomerular capillary lumina causing narrowing
(i) E0: no endocapillary hypercellularity (ii) E1: any glomeruli showing endocapillary hypercellularity
Segmental glomerulosclerosis (S)
Obliteration of capillary lumina by fibrosis in less than 50% of the glomerular tuft
(i) S0: absent (ii) S1: present in any glomeruli
Tubular atrophy/interstitial fibrosis (T)
Estimated percentage of cortical area showing atrophic tubules or interstitial fibrosis, whichever is greater
(i) T0: 0–25% of cortical area (ii) T1: 26–50% of cortical area (iii) T2: >50% of cortical area
Cellular or fibrocellular crescents (C)
Percentage of glomeruli with cellular or fibrocellular crescents; crescent is defined as extracapillary proliferation which can be Cellular: cells more than 2 cells thickness Fibrous: cellular proliferation with increased matrix (<90%), Fibrocellular: proliferation with more than 90% matrix
(i) C0: absent (ii) C1: 0–25% of glomeruli (iii) C2: ≥25% of glomeruli
