Cholesterol crystal embolization.

of toes), strongly suggests this disease. Biopsy of the skin or the kidney demonstrates cholesterol crystals, biconvex, needle-shaped clefts whitin the occluded vessel. These intraluminal lesions are often accompanied by a perivascular inflammatory reaction that may contain eosinophils [2] . The reported incidence of renal atheroembolic disease during the last 10 years seems to have increased by several reasons, such as the increased longevity of patients with atherosclerotic vascular disease that may explain the increase in the number of invasive vascular procedures and the generalized use of anticoagulants and thrombolytics [3] . In fact, cholesterol crystal embolism has been described not only in native kidneys, but also in renal allografts and in dialysis patients [1] . Piccoli et al. [4] present in this issue cholesterol crystal embolism in 6 dialysis patients, the largest experience published [4] . All patients had severe atherosclerosis, 5 had ischemic heart disease, and 4 patients had received a renal transplant, 1 of them three grafts. Interestingly, in 3 cases a precipitating factor was present, and in the other 3 patients cholesterol crystal embolization developed spontaneously. Skin manifestations were the key for the diagnosis, particularly livedo reticularis and necrotic lesions in legs, toes, and feet. Notably, steroid treatment (with prostaglandin analogs in 4 cases) was successful in the short term, although 1 patient died of sepsis, and another needed amputation performed over the knee 6 months later. From this interesting article, several points of interest should be considered. First, cholesterol crystal embolization is also a potential complication in dialysis patients, Cholesterol crystal embolization, also called atheroembolism or atheroembolic renal disease, is still an underdiagnosed entity. Atheroembolic renal disease is caused by cholesterol crystals from an atherosclerotic aorta and is a particularly severe ulcerated plaque atherosclerosis that occludes small renal arteries. The kidney is frequently involved because of the proximity of the renal arteries to the abdominal aorta. Cholesterol crystal embolization can also occur in many anatomic sites, including skin, liver, heart, pancreas, gastrointestinal tract, spleen, prostate, penis, testes, bladder, spinal cord, intracerebral vessels, retina, subcutaneous tissue, and skeletal muscle. Therefore, cholesterol crystal embolization has been considered a multisystemic disease [1–3] . Although cholesterol crystal embolization can occur spontaneously (in around 20% of the cases), it characteristically appears after an invasive vascular procedure, such as manipulation of the aorta or other large arteries during arteriography, angioplasty, or surgery. It can also occur after anticoagulant and thrombolytic treatment. The same risk factors as for atherosclerosis, such as male sex, age