PMC4531034_01
Microscopic finding of kidney biopsy with hematoxylin and eosin stain Periodic acid Schiff (PAS) stain, and Jones methionine silver (JMS) stain.. Notes: (A) Nodular sclerosis (big arrow) and thickened basement membrane (small arrow) - JMS. (B) Mesangial proliferation - PAS. (C) Neutrophil infiltration - PAS. (D) Cellular crescent. (E) RBC cast (arrow). (F) Focal acute tubular injury - JMS (arrow). (G) IF: C3 glomerulus. (H) IF: IgA glomerulus. G and H show the "starry sky" appearance.. Abbreviations: RBC, red blood cell; IF, Immunofluorescence; PIGN, post infectious glomerulonephritis.
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The glomerular basement membranes appear diffusely thickened with focal duplications. (Figure 1A) Superimposed on this nodular sclerosis, there is mild to moderate mesangial hypercellularity and segmental to global endocapillary proliferation (Figure 1B) including infiltrating neutrophils. (Figure 1C) There is endocapillary and focal extracapillary proliferative and exudative features: cellular/fibrocellular crescents; arteries and arterioles are narrowed by moderately severe intimal sclerosis; (Figure 1D) RBC casts (Figure 1E) and focal acute tubular injury. Figure 1F; the immunofluorescence (IF) findings of granular global mesangial and "starry-sky" pattern of glomerular capillary wall positivity for IgA and C3 (Figure 1G and H) support IgA-dominant post-infectious glomerulonephritis (IgA-PIGN) with endocapillary and focal extracapillary proliferative and exudative features associated with staphylococcal infection.