RESUMO
May-Thurner syndrome (MTS) is an anatomical condition resulting in compression of the left common iliac vein between the right common iliac artery and the underlying spine. MTS is rarely diagnosed because diagnostic workup is seldom continued once the diagnosis of a deep vein thrombosis (DVT) has been established. Furthermore, patients with DVT generally have several well-known confounding risk factors. We report a 16-year-old girl with a history of left leg swelling who was incidentally diagnosed with MTS. We hope that our case report will create awareness of vascular abnormalities in sports medicine and suggest that routine venous Doppler ultrasound screening may help to detect MTS or associated anatomical prior to the formation of early thrombosis.