May-Thurner Syndrome and Patent Foramen Ovale: A Rare Etiology of Cryptogenic Stroke.

Patients who present with stroke or transient ischemic attacks (TIA) in the setting of patent foramen ovale (PFO) mandate investigation of the lower extremities and pelvis in order to determine a possible source of thromboembolic disease. Imaging studies including Doppler ultrasound of the extremities may not be sufficient to diagnose the presence of anatomic variants that predispose patients to thrombus formation. May-Thurner syndrome (MTS) is characterized by extrinsic compression of the common iliac veins or inferior vena cava which leads to chronic physiologic changes within the vasculature.