[A case of leiomyosarcoma of the renal vein].

A 54-year-old woman presented with a 6-month history of left back pain. She had undergone left mastectomy for breast cancer in 1993 and hysterectomy for cervical cancer in 1997. Excretory urography showed no abnormality in the left collecting system, but right hydronephrosis caused by a midureteral stone. She was treated by transurethral ureterolithotripsy first. Computerized tomography showed a 4 x 3 cm. mass enhanced slightly by contrast medium at the left renal hilus. The tumor was bordered laterally by the left kidney and posteriorly by the left renal vein which appeared normal on magnetic resonance imaging. Selective left renal angiography revealed no abnormality. Radical en bloc excision of the tumor with the left kidney and adrenal gland was performed. Pathological examination showed a well differentiated leiomyosarcoma arising from the renal vein; the tumor cells stained positive for alpha-smooth muscle actin, vimentin and desmin and negative for S 100-protein. She was free of symptoms and there was no evidence of local recurrence or distant metastases 22 months postoperatively.