Leiomyosarcoma of the inferior vena cava (IVC) is a rare malignant tumor originating in the smooth muscle of the media. Although rare, it is the most common malignancy in the IVC. One hundred and six cases have been reported thus far in the world literature, usually as isolated case reports. Clinical, radiologic, and therapeutic management and follow-up, including 7 additional cases, have been reviewed and summarized. Clinical manifestations are dependent upon the location of the tumor. The main symptom was a palpable mass for a tumor in segment I, abdominal pain for segment II, the presence of Budd-Chiari syndrome for segment III. Segment II was the most frequent site of leiomyosarcoma of the IVC, alone (n = 41) or with other segments (n = 39). Before laparotomy, clinical recognition was difficult or impossible. Recently, however, newer imaging modalities including ultrasound and CT scan have permitted earlier diagnosis. Metastases, when diagnosed, were either present at diagnosis (n = 20) or appeared as the disease progressed (n = 18). Metastatic disease frequently involved the liver, lung, lymph nodes, or bone. The small number of patients alive without metastases (16/113) must be analyzed all the more carefully because these patients were followed for less than 2 years. When prolonged follow-up is possible, the number of patients alive without neoplastic disease is significantly reduced. We found the prognosis of patients with LMS of the IVC to be poor. Diagnosis was made at autopsy for 27 patients. Among the 86 patients with follow-up information, 59 died within a mean of 16 months, and 26 were alive 25 months after the diagnosis. The main prognostic factor is topography, particularly the highest level of extension of the tumor. The upper-segment tumors have the poorest prognosis. The best therapeutic management is difficult to recommend because most of the cases in the literature did not include a sufficient follow-up. Given the very small number of patients completely free of neoplastic disease after sufficient follow-up, it seems unlikely that leiomyosarcoma of the IVC can now be cured. Patients who received a combination of surgery, radiotherapy and chemotherapy remained free of disease for longer periods. The unanswered question is: what is the best timing for each of these treatments? We recommend diagnosis of leiomyosarcoma of the IVC through biopsy guided by ultrasonography or computed tomographic scan. Therapeutic management should include large doses of chemotherapy preoperatively with or without radiotherapy to reduce tumor size.(ABSTRACT TRUNCATED AT 250 WORDS)