Deep vein thrombosis as a presenting symptom of congenital interruption ofthe inferior vena cava

Infrahepatic interruption of the inferior vena cava is a congenital anomaly , resulting in venous drainage of the lower extremities by way of a compens atory enlarged vena azygos system. We report the case of a 37-year-old male who presented with symptoms of deep vein thrombosis of the entire right lo wer extremity. A right-sided mediastinal mass on the chest X-ray was mistak en for a haematological malignancy but proved later to represent an enlarge d azygos vein. The case illustrates that in a case of deep vein thrombosis, especially in younger patients, interruption of the inferior vena cava sho uld be considered. A right-sided paratracheal mass on the chest X-ray may g ive a clue in making the correct diagnosis.