Venous thromboembolism (VTE) can be the fi rst symptom of an occult malignancy in apparently healthy individual. Inferior vena cava (IVC) tumors are rare conditions but with negative prognosis. We present the case of a 57 year-old male patient, with complete situs inversus, diagnosed with hepatic cirrhotic disease and frequent decompensations, that was hospitalized for deep venous thrombosis (DVT) and ascites. Further imagistic investigations revealed a 22 cm tumor inside the IVC with consequent Budd-Chiari syndrome that was actually causing the liver and kidney disease, extending from the infrarenal level to the right atrium. After compensation, the patient was referred to a multidisciplinary surgical team. However, the management of such patients is very diffi cult, and the prognosis is altered. Possible IVC leiomyosarcoma are very rare and such vascular extension has been rarely reported.