Kidney - Infarct

Renal infarcts usually appear as well-demarcated, wedge-shaped or triangular areas of coagulative necrosis that extend from the capsular surface into the medulla. The characteristic shape results from the kidney’s unique vascular supply. Infarcts can arise spontaneously from a number of causes that compromise the vascular supply, such as neoplastic infiltrates or nephrotoxicants. Acute infarcts have a central area of necrosis with little peripheral inflammation (Figure 1). As the lesion progresses, neutrophilic to mononuclear infiltrates become evident near the area of necrosis (Figure 2). Chronic infarcts are characterized by renal parenchymal interstitial fibrosis and capsule surface depression (Figure 3). However, ascribing an infarct to all areas with cortical depression and fibrosis may not be warranted since some might represent areas of previous interstitial inflammation that are resolving.