We describe 3 cases of leiomyosarcoma of the inferior vena cava (IVC) and review the literature describing clinicopathologic features of 211 cases and the outcome. Of these, 74% of the cases affected women with median age of 52 years. The most common symptoms were abdominal pain or mass (57%), Budd-Chiari syndrome (17%), and deep vein thrombosis (4%). The most frequent site of tumor origin is the middle segment of the IVC (33%). Tumor size ranged from 2 to 38 cm (mean, 12 cm). Of the tumors with an assigned grade, 46% were high grade, 17% were intermediate grade, and 36% were low grade. Of all patients, 47% underwent complete resection, 24% had complete resection with preoperative or postoperative chemotherapy and/or radiation, and 5% had palliative surgery. Tumor recurrence occurred in 40% of the patients (11% had local recurrence and 29% had metastasis). Perioperative mortality occurred in 4% of the cases. Of those patients who died, 42% died of the disease, 2% died of other causes, 26% were alive and free of the disease, 14% were alive with recurrent disease, and 11% were lost to follow-up. Tumors involving level 2 of the IVC have the best prognosis and tumors of level 1 have the worse prognosis. Although there is no standardized criteria for the grading of extrauterine leiomyosarcoma, we propose to grade based on mitotic activity as follows: high grade, 10 or more mitoses per 10 high-power field (HPF); intermediate grade, 5 to 9 mitoses per 10 HPF; and low grade, 1 to 4 mitoses per 10 HPF. © 2005 Elsevier Inc. All rights reserved.