Where is the Inferior Vena Cava? A Case Report

Aim: The absence of the inferior vena cava (IVC) is a rare abnormality reported in less than 1% of the population. The collateral veins are enlarged with agenesis IVC, enabling blood transport to the superior vena cava. IVC agenesis (IVCA) may predispose to venous hypertension and complications, including thromboembolism. Case report: We present a case of a 20-year-old female patient with syncope who came to the emergency ambulance. She had profuse perspiration, and she lost 12 kg of body weight in one month. Under the suspicion of pulmonary thromboembolism, a CT (computed tomography) angiography of the pulmonary arteries showed a retrosternal para-aortic hypovascular soft tissue formation with a diameter of 30x40x85 mm. Laboratory findings also confirmed higher thyroid hormone values. Immunohyperthyroidism was diagnosed. A venous phase of CT angiograpy scan of the thorax was performed which showed that para-aortic hypovascular soft-active formation is the thymus, but an incidental finding was also discovered (Figure 1.). There was no representation of the inferior v. cava in the area from the renal veins to the heart, and the dominant azygos and hemiazygos v. were visible (Figure 2.). Hemiazygos vein merges into the azygos vein in the thorax area (Figure 3.). All the above corresponds primarily to the anatomical variant of congenital absence of v. cava inferior. Conclusion: IVCA is a significant but highly under recognized cause of unprovoked DVT (deep vein thrombosis) of the lower extremities in the young population without additional risk factors. Therefore, in unclear cases of unprovoked deep vein thrombosis of the lower extremities in the younger population, this cause should also be considered, and accordingly, the necessary diagnostic evaluation should be performed, which includes imaging for vascular anomalies along with a thrombophilic screen. Treatment is mainly conservative and may require lifelong anticoagulation therapy.