The Missing Vein: A Case of Inferior Vena Cava Agenesis Presenting With Venous Thromboembolism.

Agenesis of the inferior vena cava (IVC) is a rare congenital anomaly that is frequently identified incidentally in patients presenting with venous thromboembolism. The IVC is susceptible to a wide range of congenital anomalies. Due to its rarity and infrequent clinical encounters, it is often overlooked. We describe the case of a young man of African descent who presented with a deep vein thrombosis due to a previously unrecognized diagnosis of IVC agenesis. This case sheds light on IVC agenesis as an alternative diagnosis, especially in younger patients without traditional risk factors for venous thromboembolism.