PO153 | MAY–THURNER SYNDROME MIMICKING INFERIOR VENA CAVA SYNDROME: A CASE REPORT

M. Shani, G. Pelo, T. Goxhaj | Mother Theresa University Hospital, Università Nostra Signora del Buon Consiglio, Tirana, Albania

May–Thurner syndrome (MTS), also known as iliac vein compression syndrome, is a vascular disorder caused by compression of the left common iliac vein by the right common iliac artery. This condition leads to venous outflow obstruction and predisposes affected individuals to deep vein thrombosis (DVT). Although typically presenting with unilateral lower limb swelling, MTS may rarely mimic inferior vena cava (IVC) syndrome, presenting with bilateral lower extremity edema and extensive venous congestion. We report a case of May–Thurner syndrome initially suspected to be inferior vena cava obstruction due to the presence of bilateral lower limb swelling and dilated abdominal wall veins. Imaging studies ultimately demonstrated severe compression of the left common iliac vein with extensive collateral circulation. Endovascular management resulted in clinical improvement. This case highlights the importance of considering May–Thurner syndrome in the differential diagnosis of venous outflow obstruction and illustrates how extensive collateralization may mimic IVC syndrome.
Case Presentation. Patient Information; a 42-year-old female presented to the emergency department with progressive swelling of both lower extremities for two weeks. The swelling was associated with mild discomfort and heaviness while walking. The patient denied recent trauma, prolonged immobilization, malignancy, previous thromboembolic events. She reported no significant past medical history and was not taking oral contraceptives. Clinical Findings; physical examination revealed: bilateral lower limb edema extending to the thighs, prominent superficial abdominal veins, and mild tenderness of the left calf. Vital signs were stable. No signs of heart failure or liver disease were observed. Because of the bilateral nature of the swelling, initial clinical suspicion was directed toward inferior vena cava obstruction. Diagnostic Assessment; laboratory investigations revealed mildly elevated D-dimer levels, normal coagulation profile, and normal liver and renal function tests. Thrombophilia screening was negative. Discussion; may–Thurner syndrome represents an underdiagnosed cause of venous outflow obstruction. Studies suggest that up to 20–30% of individuals may have some degree of iliac vein compression, although only a minority develop clinically significant symptoms. Pathophysiology; the primary mechanism involves chronic pulsatile compression of the left common iliac vein by the overlying right common iliac artery. This leads to: endothelial injury, intimal hypertrophy, formation of fibrous spurs, venous stasis. Together, these changes fulfill Virchow’s triad, promoting thrombosis. Mimicking Inferior Vena Cava Syndrome; in advanced cases, extensive collateral venous networks develop within the pelvis and abdominal wall. These collateral pathways may produce clinical findings similar to inferior vena cava syndrome, including: bilateral leg swelling dilated abdominal wall veins, pelvic venous congestion. Because the inferior vena cava remains patent, diagnosis requires advanced imaging modalities such as CT or MR venography.