Abstract: PO1425
Collapsing FSGS or Crescentic GN or Both: A Diagnostic Challenge
Session Information
- Glomerular Diseases: Immunology and Inflammation in Vasculitis and Lupus Nephritis
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Malek, Irshadjahan, Division of Nephropathology, University of North Carolina, Chapel Hill, North Carolina, United States
- Singh, Harsharan Kaur, Division of Nephropathology, University of North Carolina, Chapel Hill, North Carolina, United States
- Nickeleit, Volker, Division of Nephropathology, University of North Carolina, Chapel Hill, North Carolina, United States
Introduction
The finding of an ANCA associated necrotizing & crescentic GN with collapsing FSGS is a rarity with only few reported cases in literature.
Case Description
A 53-yr-old AA female was admitted to hospital with difficulty in swallowing, poor oral intake, hemoptysis & AKI superimposed on CKD-III with hx of HTN & use of NSAIDs. Urine analysis showed hematuria, proteinuria & UPC ratio of 4.15. Blood analysis showed S.Cr 8.7mg/dl, BUN 60mg/dl, Albumin 2.4gm/dl, positive MPO ANCA & ANA titers. By light microscopy 36 glomeruli were present, 20% showed cellular/fibro-cellular crescent formation with underlying tuft fibrinoid necrosis & 20% showed collapsing FSGS. ATI, moderate IF/TA & moderate to severe arteriosclerosis were present. EM showed global podocyte activation with foot processes effacement.
Discussion
Collapsing FSGS and ANCA associated GN can both present with abrupt onset AKI & proteinuria. No specific test exists to separate crescents from collapsing FSGS; therefore this daunting differentiation requires a high level of suspicion, often relegated to experience. Most useful morphologic features are summarized in table 1. In our case, AA race (possible APOL1 risk variants) & underlying severe arterionephrosclerosis (ischemia) are the most likely etiologies for the collapsing FSGS.
| Morphology | Collapsing FSGS | Crescentic GN |
| Tuft Collapse | ++ | - |
| Podocytes hyperplasia/hypertrophy | ++ | - |
| Parietal epithelial cell hyperplasia | - | ++ |
| Tuft fibrinoid necrosis | - | ++ |
| Fibrin in extra capillary space | +/- | ++ |
| Podocytes protein resorption droplets | +++ | +/- |
| Inflammatory cells in extra capillary proliferation | - | + |
| Spindle cell elements/Myofibroblasts | - | + |
| Extracellular matrix deposition | + | + |
| Interstitial inflammation | + | -/++ |
| RBC casts | - | ++ |
| ATI | + | + |
| Tubular microcystic dilation | +++ | +/- |
A-Tuft collapse(arrow), podocytes hyperplasia/hypertrophy. B- Fibrinoid necrosis (arrow) & crescent formation(Trichrome stain x20)