Which pathology is characterized on angiography as a "string of beads" appearance?

The "string of beads" appearance on angiography is a classic feature associated with fibromuscular dysplasia. This condition primarily affects the medium-sized arteries, particularly the renal and carotid arteries, and is characterized by alternating stenosis and aneurysms in the vascular wall.

The signature "string of beads" appearance arises from the presence of multiple luminal stenoses associated with outpouchings or aneurysms, which give a beaded appearance along the length of the affected artery. This pattern provides a visual distinction that helps radiologists and vascular technologists identify fibromuscular dysplasia during imaging studies.

In contrast, atherosclerosis typically presents as focal lesions with a gradual narrowing of the vascular lumen, and does not have the characteristic beaded pattern. Vasculitis may cause irregularities and stenosis but does not specifically result in the "string of beads" appearance. Neoplasia can lead to vascular compression or obstruction, but again lacks this specific angiographic feature. Therefore, the distinct characteristics of fibromuscular dysplasia make it the correct choice for this angiographic description.