Posterior Nutcracker Syndrome in a Patient With Circumaortic Venous Ring: Lessons Learned From a Case Report

Vascular compression syndromes are a group of rare conditions caused by compression of vascular and nervous structures, as well as from masses or other adjacent vascular structures. In nutcracker syndrome, the left renal vein is compressed before the confluence into the inferior vena cava, in the anterior aortomesenteric space (i.e., anteroaortic vein) or in the aortovertebral space (i.e., retroaortic vein). When compression is significant, it manifests clinically with low back pain, microhematuria, proteinuria, venous thrombosis, and varicocele. Computed tomography allows easy identification of this type of compression and its origins. This case report describes a rare occurrence of a renal collar with symptomatic compression of the posterior left renal vein.