Inferior Vena Cava Agenesis as Cause of Pulmonary Embolism: Case Report and Literature Review.

Introduction: Inferior vena cava agenesis (IVCA) is a very uncommon vascular condition, occurring in about 0.0005% to 1% of the population. It is often overlooked as a potential cause of deep venous thrombosis and pulmonary embolism, particularly in younger patients.

Case presentation: A 25-year-old Hispanic woman presented to the emergency department with leg swelling and pain. She later developed shortness of breath and chest pain, prompting her transfer to the intensive care unit. Chest and abdominal computed tomographic angiography confirmed a left pulmonary embolism, absence of the infrarenal vena cava, and a thrombus in the left superficial iliac and femoral veins. She was treated with thrombolytic therapy followed by a successful thrombectomy.

Discussion: IVCA is a rare vascular condition caused by either a developmental failure of the inferior vena cava or thrombosis with secondary resorption. This leads to a complex collateral venous system with slower blood flow, increasing the risk of stasis and thrombus formation. IVCA should be considered in young patients with recurrent thromboembolism who lack typical risk factors. Diagnosis is best achieved through computed tomography or magnetic resonance angiography. Management usually involves long-term anticoagulation, with surgery reserved for select cases.

Conclusions: IVCA is an uncommon cause of thromboembolism events. It is important to consider this diagnosis in young patients after immune, genetic, or traumatic issues have been ruled out, as prompt treatment can help prevent serious health risks.