Version August 2025
| Glomerular lesions | |
| Mesangial hypercellularity | >3 mesangial cells per mesangial area |
| Cellular crescent | Extracapillary cell proliferation of more than two cell layers with >50% of the lesion occupied by cells |
| Fibrocellular crescent | An extracapillary lesion comprising cells and extracellular matrix, with <50% cells and <90% matrix |
| Fibrous crescent | Extracapillary crescents with >90% matrix |
| Endocapillary hypercellularity | Hypercellularity caused by an increased number of cells within glomerular capillary lumina, causing narrowing of the lumina |
| Fibrinoid necrosis | Disruption of the GBM with fibrin exudation |
| Sclerosis | Obliteration of the capillary lumen by increased extracellular matrix with or without hyalinosis or foam cells |
| Patterns of GN | |
| Minimal mesangial GN* | Normal glomeruli by LM but mesangial immune deposits by IF |
| Mesangial proliferative GN* | Purely mesangial hypercellularity |
| Active (proliferative) GN* | Any or all of the following glomerular lesions: endocapillary hypercellularity, karyorrhexis, fibrinoid necrosis, rupture of GBMs, cellular or fibrocellular crescents, subendothelial deposits identifiable by LM, and intraluminal immune aggregates |
| Necrotizing GN | Segmental or global fibrinoid necrosis |
| Crescentic GN | ≥50% glomeruli with cellular, fibrocellular, or fibrous crescents (with percentage of crescents always noted in the diagnostic line, even when <50%)¶ |
| Membranoproliferative GN | Mesangial and/or endocapillary hypercellularity and thickening of capillary walls caused by subendothelial Ig and/or complement factors |
| Exudative GN | Neutrophils accounting for >50% of glomerular hypercellularity |
| Sclerosing GN* | Any or all of the following glomerular lesions: glomerular sclerosis, fibrous adhesions, and fibrous crescents |
ANCA: antineutrophil cytoplasmic autoantibody; C3GN: C3 glomerulonephritis; GBM: glomerular basement membrane; GN: glomerulonephritis; IF: immunofluorescence; Ig: immunoglobulin; IgA: immunoglobulin A; ISN/RPS: International Society of Nephrology/Renal Pathology Society; LM: light microscopy.
* Except for the first two patterns, multiple patterns can occur together in a single specimen (derived from the ISN/RPS lupus classification[1]).
¶ The term crescentic GN is used when crescents are present in at least 50% of glomeruli and applies to immune-complex C3GN glomerulopathy. This does not apply to ANCA GN and anti-GBM GN, where less than 50% of the glomeruli may be involved by crescents.Reproduced with permisison from: Sethi S, Haas M, Markowitz GS, et al. Mayo Clinic/Renal Pathology Society consensus report on pathologic classification, diagnosis, and reporting of GN. J Am Soc Nephrol 2016; 27(5):1278-1287. Copyright © 2016 American Society of Nephrology. https://journals.lww.com/jasn/pages/default.aspx.
