[Vena cava inferior agenesia as a retroperitoneal mass].

This case-report presents a young man with a random finding of a retroperitoneal mass due to a vena cava inferior agenesia with an ectatic cavity. This probably caused a severe pulmonary embolism six years before in this previously healthy man. No other hereditary factors were found at the screening for thrombophilia. We describe the potential differential diagnostic difficulties of such cases.