May–Thurner Syndrome in an Adolescent Male with Celiac Disease and Homozygous Factor V Leiden Mutation: A Case Report

May–Thurner syndrome (MTS) is a rare cause of venous thromboembolism (VTE) in children and adolescents and is often underdiagnosed. Here we present an adolescent male with extensive iliofemoral deep vein thrombosis (DVT) in whom MTS was identified as one of several contributing etiological factors. His first presentation revealed acute unilateral swelling and pain in the left lower extremity following minor trauma. Doppler ultrasonography disclosed extensive acute iliofemoral DVT, and further evaluation by computed tomography angiography demonstrated extrinsic compression of the left common iliac vein by the right common iliac artery, consistent with May–Thurner syndrome. He was also found to have homozygous Factor V Leiden mutation, probable hereditary protein C deficiency, hyperhomocysteinemia, and celiac disease, together indicating a multifactorial thrombotic process. This case highlights the importance of considering anatomical venous compression syndromes in adolescents presenting with extensive and unexplained iliofemoral DVT.

Keywords: May–Thurner syndrome, Deep vein thrombosis, Factor V Leiden, Pediatric