Figure 2.

(a) De novo arteriolar hyalinosis involving the muscularis of an afferent arteriole in a kidney allograft recipient with late graft dysfunction. Note the beaded nature of the hyaline accumulation (arrows, periodic acid–Schiff, original magnification ×400). (b) Electron microscopy from a kidney allograft recipient with late allograft dysfunction attributed to chronic calcineurin inhibitor toxicity reveals hyaline accumulation within the muscularis of an afferent arteriole bulging to the adventitia of the vessel (arrow, electron microscopy, original magnification ×5000). (c) Electron microscopy from a patient with diabetic glomerulosclerosis who was never exposed to calcineurin inhibitors. Note the prominent subendothelial hyaline accumulation. However, this hyalinosis focally extends to the muscularis and bulges to the adventitia to cause a vague beaded appearance (arrows). This finding is rarely observed in diabetic or hypertensive patients (electron microscopy, original magnification ×3000).