Acute bilateral pulmonary embolism in a 21-year-old: is May-Thurner syndrome in our differential?

May-Thurner syndrome (MTS) is a clinical condition where the left common iliac vein gets compressed by the overlying right common iliac artery anterior to the fifth lumbar vertebra and the sacral promontory. It results in vessel wall injury and predisposition to thrombosis. We present a case of a 21-year-old African-American man with no significant past medical history who came to the emergency department with left lower limb swelling associated with shortness of breath, and was eventually diagnosed to have extensive left lower extremity deep vein thrombosis (DVT) along with acute bilateral extensive pulmonary embolism (PE) as a consequence to MTS. MTS should be considered in the differential when young patients present with unprovoked or recurrent left-sided DVT. Diagnosis of this anatomical variant is critical as it may need long-term anticoagulation and consideration of pharmaco-mechanical intervention such as mechanical thrombectomy and venoplasty with or without stenting. © BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.