Leiomyosarcoma of the renal vein.

The preoperative diagnosis for primary leiomyosarcoma of the renal vein, an extremely rare tumor, is difficult. The tumor predominantly occurs in women and on the left side. Its natural history is toward distant metastases and a poor 5-year survival rate. Nephrectomy and en-bloc surgical resection remain the mainstay of therapy. We present three such cases and review the world literature.