Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a nonatheromatous, noninflammatory proliferative process affecting long unbranched segments of medium-sized conduit arteries such as the renal artery and the internal carotid artery; however, it has been observed in almost every artery in the body. It typically affects women. The clinical manifestations involve the spectrum of arterial obstruction and/or aneurysmal degeneration and depend on the arterial bed involved. Based on angiographic criteria, it can be multifocal, characterized by the “string-of-beads” appearance, or focal, with a single area of stenosis. FMD is the second most frequent cause of renal artery stenosis after atherosclerosis and the most common cause of renal hypertension in young individuals. Carotid FMD is less frequent and may cause cerebrovascular symptoms, although it usually remains asymptomatic and has a relatively benign natural history. Treatment options can be medical/conservative, endovascular, and/or surgical depending on the patient's comorbidities and the severity and anatomy of the lesions.