PMC5438016_01
Renal biopsy histology demonstrating focal segmental proliferative and necrotizing glomerulonephritis. A: Glomerulus with segmental proliferation and crescent (hematoxylin-eosin stain, x200). B: Glomerulus with segmental necrosis and crescent (Jones silver stain, x200). C: Glomerulus with cellular crescent and interstitial fibrosis (Masson trichrome stain, x200). D: Two glomeruli with fibro-cellular lesions and scarring indicative of chronicity (hematoxylin-eosin stain, x200).
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Figure1
A low C3 (0.5 g/L) and C4 (0.07 g/L) and strongly positive PR3-ANCA (> 8.0 AI) with a negative p-ANCA prompted renal biopsy that revealed focal segmental proliferative and necrotizing glomerulonephritis affecting > 50% of glomeruli with cellular and fibrocellular crescents and some segmental sclerosis (Figure 1), indicative of chronicity.
Part of glomerulus with focal fusion of foot processes (arrow) and absence of immune complexes (electron microscopy, x8,000).
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Figure2
Immunofluorescence and electron microscopy demonstrated a paucity of any significant immune complexes (Figure 2), and, given the severity and extent of necrotizing lesions, a diagnosis of pauci-immune GN consistent with ANCA vasculitis was made. 