Intravenous leiomyomatosis with inferior vena cava or intracardiac extension and concurrent bilateral multiple pulmonary nodules

Background: Intravenous leiomyomatosis is a special type of uterine leiomyoma and features formation and growth of benign leiomyoma tissue within vascular wall. Benign metastatic leiomyoma refers to benign leiomyoma metastasizing to extra-uterine sites, dominantly lung. Solitary or multiple small nodules in the lung can be seen in image scans. Methods: We report 2 cases of intravenous leiomyomatosis with inferior vena cava or intracardiac extension and concurrent multiple nodules in bilateral lungs. Results: Case 1 was a 40-year-old woman with a large mass in pelvic cavity, masses in heart chambers, and disseminates pulmonary nodules detected at preoperative image scans. Masses in pelvic cavity and heart were resected in a 2-stage surgery. Histology examination confirmed the diagnosis of intravenous leiomyomatosis. Pulmonary nodules stayed stable during follow-up. Case 2 was a 37-year-old woman with 3 times of uterine-related surgeries. A pelvic mass appeared again and filling defect was observed in left ovarian vein, right renal vein, right common iliac vein, and inferior vena cava. Tumors in pelvic cavity and within vessels were removed in a 1-stage surgery. Histology examination confirmed the diagnosis of intravenous leiomyomatosis. Pulmonary nodules remained stable during follow-up. Conclusion: The incidence of benign metastatic leiomyoma in patients with intravenous leiomyomatosis might be relatively high. Metastasis of intravenous leiomyomatosis lesions was a possible source of benign metastatic leiomyoma in these cases.