Median arcuate ligament syndrome (MALS) is caused by extrinsic compression of the celiac trunk by the median arcuate ligament. While compression of the celiac trunk is more common, other arteries, including the renal arteries, can be affected. Renal artery entrapment by the arcuate ligament was first described in 1962, and only a few cases have been reported. This condition represents a rare cause of secondary hypertension in young individuals, and early recognition is essential to prevent long-term renal damage.

Case Report
Mr. F.R., a 22-year-old medical student with no past medical history, was diagnosed with hypertension. An abdominopelvic CT scan was performed, complemented by a PET scan at Tenon Hospital to investigate lymphadenopathy; no hypermetabolic activity was observed, but renal asymmetry and right renal artery stenosis were noted. Further imaging at Georges Pompidou Hospital, including renal artery Doppler ultrasonography and CT, confirmed significant stenosis of the right renal artery with intrarenal hemodynamic consequences.

Measured velocities reached 4 m/s, and the right kidney was reduced in size (10 cm vs. 13 cm on the left). Two right renal arteries were present, both thin and collapsed, with subocclusion of the proximal segments, and a prominent right diaphragmatic crus in close contact. No adenopathy was observed.(figure 1).

Figure 1: CT scan demonstrating right renal artery stenosis and renal asymmetry.

The patient underwent surgery under general anesthesia via a right subcostal approach. The right renal artery was dissected retrocavally, revealing the median arcuate ligament(Figure2)

Figure 2: Intraoperative view of left renal artery compression by the median arcuate ligament.

The muscular portion was divided with electrocautery, and the fibrous portion was sectioned with scissors. The artery remained fibrotic, and a right aorto-renal bypass using a PTFE graft (Figure3) was performed. The postoperative course was uneventful. At three months follow-up, the patient had resumed his studies and daily activities, the surgical scar was clean, and blood pressure had normalized, allowing discontinuation of antihypertensive medications.

Figure 3: Right aorto-renal bypass with PTFE graft placement following ligament decompression.