The photomicrograph shows an infarct that has undergone fibrous scarring. Note the depression of the cortical surface below the level of the adjacent normal cortex. This trichrome stains shows a blue color to the lesion, indicating excess collagen.
Most renal infarcts are the result of embolized thrombi that lodge in renal arterial vessels.
The epidemiology is that of the primary disease process affecting the heart, i.e, atherosclerotic cardiovascular disease, infectious endocarditis. On cut section, renal infarcts are triangular with the base at the cortical surface and the apex pointing towards the medulla and the occluded artery. A day or so after occlusion, the infarct appears pale compared to adjacent parenchyma. Old resolved infarcts on cut section show a V shape absence of renal parenchyma. Recent infarcts show coagulative necrosis where the native renal architecture is discernible but the tissue is necrotic.