Leiomyosarcoma of the inferior vena cava is a rare lethal malignancy. The authors report the seventy-sixth case of the literature and the sixth displayed by computed tomography. CT is presently the radiological modality of choice to localize the site and extension of the tumour, but a cavogram must also be obtained since it displays, much better than CT, the collateral veins and gives a synthetic longitudinal view of the tumour.