Malignant hypertension caused by renovascular disease. The renal artery is narrowed by atherosclerotic plaque causing an elevation in blood pressure. The increased pressure damages the walls of the small arterioles and glomerular capillaries in the cortex. The vessels rupture causing hemorrhage and infarction (scarring). The granular surface of the kidney indicates atrophy and fibrosis of the cortex due to the destruction of the small blood vessels.