Rare case of biopsy proven inferior vena cava (IVC) leiomyosarcoma. The patient died shortly after admission. The primary mass is along the rightward aspect of the inferior vena cava (extravascular), and extends intravascularly. There is enhancing tumor thrombus and bland thrombus filling the inferior vena cava to the right atrium, resulting in hepatic venous obstruction (Budd Chiari).