PMC5830811_01
(a) Glomerulus revealing lobular accentuation with global proliferative tufts (PAS, x400). (b) Thick linear accentuation of capillary walls, along with mesangial granular deposits forming mesangial rings with C3 of 3+ intensity (x400)
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F1
Renal biopsy showed 12 viable glomeruli revealing diffuse endocapillary proliferative changes with markedly thickened capillary basement membranes (periodic acid-Schiff [PAS]-positive and silver-weak positive) [Figure 1a]. Immunofluorescence showed granular positivity with C3 (3+) along the capillary walls and mesangial region [Figure 1b].
(a) Thickened glassy capillary basement membranes with double contour appearance and proliferation of endothelial cells/mesangial cells (PAS, x400). (b) Globally sclerotic glomerulus with relatively preserved broad basophilic capillary walls (Mason trichrome, x400). (c) Similar C3 positivity with mesangial rings as seen in the first biopsy (x400). (d) Band of granular positivity for C4d along the peripheral capillary walls (IHC, x400)
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F2
Light microscopy and immunofluorescence were similar to prior biopsy, except for the presence of focal global and segmental sclerotic lesions in 2 and 1 glomeurli [Figure 2a-c], respectively of total 10 glomerulil with 5 glomeruli being obsolescent; along with mild tubulointerstitial chronicity. Surprisingly, positive granular staining reaction was seen that mirror-imaged C3 staining [Figure 2d].
Ultrastructure study showing ribbon like osmiophilic deposits replacing the lamina densa of capillary basement membranes; with similar mesangial deposits and proliferative tufts (x10,000)
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F3
EM performed on the second biopsy showed ribbon-like osmiophilic transformation of capillary basement membranes; rarely along Bowman's capsule and tubular basement membranes [Figure 3].