Fibromuscular dysplasia may show a 'string of pearls' appearance in which arteries?

• A. Renal arteries
• B. Carotid arteries
• C. Pulmonary arteries
• D. Mesenteric arteries

Answer: (A)

Fibromuscular dysplasia is a non-atherosclerotic arterial disease that causes irregular thickening of the artery wall, leading to alternating segments of narrowing and dilation on imaging. This pattern creates the characteristic “string of beads” appearance on angiography.

The renal arteries are the most classic and common site for this finding. When the renal arteries show this beaded contour, it explains why renovascular hypertension is often seen in patients with FMD. While the same pattern can occasionally be observed in other arteries, such as the carotids, the kidneys are the prototypical location for this sign, making renal arteries the best answer among the choices. Pulmonary and mesenteric arteries are not typical primary sites for fibromuscular dysplasia.