Fact-sheet: Fibromuscular dysplasia


Updated on 02/06/2026 at 5:23 PM

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Definition

Fibromuscular dysplasia is a group of rare, idiopathic, segmental, noninflammatory, and nonatheromatous arterial wall diseases resulting in stenoses of small and medium-caliber arteries.

Clinical features

Symptomatology depending on the territories involved

  • Hypertension due to renal artery involvement
  • Neurologic signs due to involvement of the neck vessels or rupture of an intracranial aneurysm
  • Angina or sudden death due to coronary artery involvement
  • Peripheral arterial disease due to involvement of the lower limb arteries

Predominance: women aged 30 to 50 years.

Laboratory findings

Advanced-stage renal failure

Ultrasound

Renal duplex Ultrasound: irregular appearance of the artery or tandem stenoses.
Renal asymmetry.

CT

CT angiography:

  • Characteristic appearance of the multifocal form as a "string of beads" or "beaded necklace" pattern, allowing the diagnosis to be established.
  • Focal form: concentric or tubular stenosis
  • Associated signs: Tortuous arteries
  • Aneurysm(s)
  • Arterial dissection
  • Subarachnoid hemorrhage
  • Downstream organ consequences: renal size asymmetry, stroke, etc.

MRI

MR angiography: same findings as on CT.

Vascular intervention

X-Ray Angiography: reference examination, but reserved for patients requiring endovascular treatment (as risk > benefit otherwise).

Classification

No classification, but value in quantifying arterial stenoses:

  • total length of lesions
  • number of diaphragms or pseudoaneurysms
  • presence of collateral circulation, a jet sign, or a small downstream kidney

Differential diagnosis

  • Atherosclerotic or inflammatory stenoses of small- or medium-caliber vessels.
  • Sympathomimetic and ergot derivative intoxication (may have the same radiologic appearance).