Thrombotic microangiopathy after renal transplantation: Current insights in de novo and recurrent disease

Table 1 Morphological features in microangiopathy

Active lesions	Chronic lesions
Glomeruli: Thrombi - Endothelial swelling or denudation - Fragmented RBCs - Subendothelial flocculent material. EM: Mesangiolysis - Microaneurysms	Glomeruli: LM: Double contours of peripheral capillary walls, with variable mesangial interposition - EM: New subendothelial basement membrane - Widening of the subendothelial zone
Arterioles: Thrombi - Endothelial swelling or denudation-Intramural fibrin-Fragmented red blood cells-Intimal swelling-Myocyte necrosis	Arterioles: Hyaline deposits Arteries: Fibrous intimal thickening with concentric lamination (onion skin)
Arteries: Thrombi - Myxoid intimal swelling -Intramural fibrin- Fragmented red blood cells

Adapted from: Goodship et al[58]. EM: Electron microscopy; LM: Light microscopy.