May-Thurner Syndrome Presenting as Acute Unexplained Deep Venous Thrombosis.

May-Thurner syndrome (MTS) is a rare cause of deep venous thrombosis and occurs due to an anatomic anomaly which produces chronic compression of the left common iliac vein by the overlying right common iliac artery when it passes between the right common iliac artery and the spine. Prolonged compression on the vein potentiates thrombus formation by impairing the intima and by leading to the development of membranes within the lumen that may decrease and/or block venous flow. In this case presentation, we elaborate on a case of a 43-year-old woman who presented with worsening left leg swelling and pain. The patient was diagnosed with MTS and underwent successful stent placement to relieve the compressed vein.