[The morphopathological aspects of diabetic retinopathy]

Nonproliferative diabetic retinopathy is characterized by the thickening of the basal membrane and the degeneration of pericytes with the appearance of microaneurysms. In a more advanced stage, there appear hemorrhages, initially in the external plexiform layer and dense exudates deriving from plasmatic extravasations and cystoid macular edema. The proliferative retinopathy is manifested by capillary obstruction with the appearance of dysoric nodules as a consequence of the lack of capillary perfusion and of some varicose capillary dilatation at the periphery of the anoxic zones. The last stage is that proliferative of retinopathy with the appearance of fibrous proliferations and neovessels. An illustration is made of the characteristic chromopathologic aspects, using hematoxilin-eosin staining, Goldner-Szekelly trichromic and Bilshuwski argentic impregnation.