PMC6431373_01
Clinical course of the patient after introduction of tacrolimus treatment. *: surgical operation, Cr; creatinine, UP; proteinuria, and BP; blood pressure.
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Clinical course after introduction of tacrolimus is shown in Figure 1. One year after renal biopsy, serum creatinine was 4.03 mg/dL and proteinuria was 1.0 g/g creatinine (Figure 1).
Light micrographs of renal tissues. (a) A glomerulus (asterisk) is mildly enlarged, showing focal segmental glomerulosclerosis while another glomerulus exhibits collapsed capillary tuft (arrowhead). Dilated tubules with flattened epithelial cells containing proteinaceous casts are present (arrow) (periodic acid-Schiff stain; original magnification x200). (b) Several glomeruli have collapsed capillary tufts (arrows). There is an extensive striped pattern of interstitial fibrosis and tubular atrophy (Elastica-Masson staining; original magnification x200). (c) A glomerulus is globally sclerotic (asterisk). There is organized thrombus formation within an afferent arteriolar lumen (arrowhead). Concentric intimal hyperplasia of arterioles forming "onion skin" lesion is noted (arrow) (periodic acid-Schiff stain; original magnification x200). (d) Glomerular capillary wall is segmentally thickened showing double contour (arrow) (periodic acid-Schiff stain; original magnification x400). (e) Arteriolar lumina are occluded by fibrous intimal thickening with recanalization. Nodular hyalinosis of arterial walls is noted (arrow) (periodic acid-Schiff stain; original magnification x400). (f) An arteriolar wall shows circumferential and transmural hyalinosis forming peripheral nodules (periodic acid-Schiff stain; original magnification x400).
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A renal biopsy showed 5 glomeruli with adhesive lesions and segmental sclerosis or global sclerosis and 8 glomeruli with ischemic shrinkage of glomerular tufts out of 22 obtained glomeruli (Figures 2(a), 2(b), and 2(c)). Some of the remaining glomeruli showed collapse of capillary tufts (Figures 2(a) and 2(b)), FSGS (Figure 2(a)), and segmental thickening of capillary walls showing double contour (Figure 2(d)). There were extensive tubular atrophy and interstitial edema to fibrosis involving 70% of renal parenchyma, accompanied by chronic and acute inflammatory cell infiltration (Figures 2(a) and 2(b)). Distribution of the tubulointerstitial damage was zonal, indicative of ischemic injury following vascular compromise (Figure 2(b)). The afferent arteriole of the glomerulus was occluded by an organized thrombus, and the arterioles showed concentric intimal hyperplasia forming "onion skin" lesion (Figure 2(c)). Some of the small arterial and arteriolar lumina were markedly narrowed by thickened fibrous intima (Figure 2(e)). Of note, some arteriolar walls exhibited circumferential and transmural nodular hyalinosis (Figures 2(e) and 2(f)).
Electron micrograph of a glomerulus. Swollen glomerular endothelial cells with loss of fenestrations, irregularity thickened lamina rara interna with small remnants in the subendothelial spaces (arrowheads), and partial foot process effacement are seen. Bar=5.0 mum.
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Electron microscopy revealed swollen glomerular endothelial cells with loss of fenestrations, irregularly thickened lamina rara interna, and foot process effacement involving 30% of podocytes (Figure 3).