May-Thurner syndrome, an uncommon diagnosis for a common disease: a case report and review of the literature

May-Turner syndrome is a relatively uncommon anatomical variation in which patients develop iliofemoral deep vein thrombosis (DVT) due to venous occlusion. In this syndrome, the left common iliac vein is compressed against the fifth lumbar vertebra by the right common iliac artery. The real incidence/prevalence of May-Turner syndrome is not precisely known, but it is estimated to be between 22 - 32% based on imaging studies. However, this syndrome is hardly ever considered in DVT diagnosis, especially in individuals with other risk factors. This venous occlusion may cause several symptoms such as leg swelling, venous thrombosis, or even more serious complications including pulmonary embolism.  The use of systemic anticoagulants alone is inefficient for the treatment of May-Turner syndrome, and more aggressive approaches are necessary to prevent clots recurrence. In this article, we described a case of a young woman suffering from pain and progressive swelling of the left lower limb without any provoking factors. With a comprehensive diagnostic approach including Doppler ultrasound and seeing a thrombus in the external iliac and left femoral veins and obstruction of the left common iliac vein in the venography images, it was determined that she has iliac vein compression syndrome. When facing unilateral venous thromboses, especially in younger age groups, the differential diagnosis should also consider May-Turner syndrome.