PMC5364195_01
The microscopic findings on renal biopsy. A: periodic acid-Schiff (PAS) staining shows massive nodular lesions at the vascular pole of glomeruli extending to the mesangial areas with weakly positive PAS staining. The arteries and arterioles were replaced with weakly PAS-positive materials throughout the layers, and the lumen was severely stenosed or occluded. Atrophic tubules and interstitial fibrosis were present, with moderate mononuclear cell infiltration and slight tubulitis (original magnification, 200x). B: Congo-red staining shows positivity in weakly PAS-positive lesions in glomeruli, arterioles, and small arteries, as well as in some interstitial areas (original magnification, 200x). C: Immunofluorescence for lambda shows positivity on massive nodular lesions at the vascular pole of the glomerulus extending to the mesangial area and small arteries. g: glomerulus, v: vasculature (original magnification, 200x) D: Electron microscopy shows amyloid deposition at the mesangial area (*), with randomly disposed amyloid fibrils on higher magnification (inset, Bar=0.5 microm). Bar 5 microm.
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Renal biopsy performed a week after admission showed 7 globally sclerosed glomeruli out of 20, 2 glomeruli with mild mesangial expansion, and the remaining 11 glomeruli had massive nodular lesions at the vascular pole, extending to the mesangial areas with weak positive periodic acid-Schiff (PAS) staining (Fig. 1A). The arteries and arterioles were replaced with weakly PAS-positive deposits throughout the layers, and their lumen were severely stenosed or occluded (Fig. 1A). Tubular atrophy and interstitial fibrosis with mononuclear cell infiltration were found in about 70% of tubulointerstitial areas, with the occasional presence of tubulitis (Fig. 1A). Congo-red staining showed positivity in the areas corresponding to weakly PAS-positive deposits (Fig. 1B). Kappa light chain was negative, but lambda light chain was strongly positive in the arterial walls and the glomeruli (Fig. 1C). Electron microscopy revealed amyloid fibrils in the mesangial areas (Fig. 1D) and the glomerular capillary walls.
A: Electrocardiogram showing low-voltage QRS complexes in limb leads. B: Echocardiogram showing thickened ventricular walls and a thickened ventricular septum with nonhomogenous granular sparking echoes. LV: left ventricle, RV: right ventricle, LA: left atrium, Ao: aortic outflow
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However, diffuse low voltage in the electrocardiogram (Fig. 2A) and granular sparkling sign of the thickened ventricular septum (16 mm) with severely impaired systolic/diastolic function on cardiac ultrasonography (Fig. 2B) indicated the presence of cardiac amyloidosis.
Direct fast scarlet staining shows positivity in the small artery walls in abdominal wall fat tissue (original magnification, 200x).
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In addition, abdominal wall fat aspiration was positive for direct fast scarlet staining in the small artery walls (Fig. 3).