AUTHOR=Ji Lianfu , Yang Fan , Chen Xuan , Chen Jinlong , Cheng Xueying , Yin Jie , Qin Yuming , Yang Shiwei TITLE=Case Report: Rare Iliac Vein Compression (May–Thurner) Syndrome in a Pediatric Patient JOURNAL=Frontiers in Pediatrics VOLUME=Volume 9 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2021.694782 DOI=10.3389/fped.2021.694782 ISSN=2296-2360 ABSTRACT=Iliac vein compression syndrome (IVCS) or May-Thurner syndrome occurs predominantly in young to middle aged women. Here we reported a case of iliac vein compression syndrome in a 5-year-old boy. The child was admitted to our vasculocardiology deparment with left lower extremity swelling present for 1 month. Blood tests revealed coagulation routine and platelets in the normal ranges. Computer tomography angiography (CTA) and Magnetic resonance imaging (MRI) showed left common iliac vein become narrow before it entered the right common iliac vein. To further clarify, we performed angiography, which clearly showed the stenosis and the blood return of the iliac vein of the left common iliac vein. So Iliac vein compression syndrome was diagnosed. What is more, we found aorta descended to the right of spine and this may be the reason for the apparent compression of left common iliac vein. For the children was young and had mild symptoms, we treated the patient conservatively mainly including elevation of the affected limb, wearing medical elastic socks and oral aspirin for anticoagulation. The boy is followed-up closely, and stent placement may need to be considered in the future.