Spontaneous disappearance of multiple lung metastases after nephroureterectomy from sarcomatoid carcinoma of the renal pelvis: a case report.

We report a case in which lung metastases disappeared spontaneously after nephroureterectomy from sarcomatoid carcinoma of the renal pelvis. A 58-year-old man presented with gross hematuria. Computed tomography (CT) revealed a left renal tumor and multiple lung metastases. Intravenous pyelography revealed a filling defect in the upper renal calyx. Urine cytology was positive. Left renal pelvic cancer was diagnosed and nephroureterectomy performed. The resected specimen was diagnosed pathologically as sarcomatoid carcinoma of the renal pelvis. Approximately 5 months later, CT revealed that the lung metastases had disappeared. There has been no evidence of disease for 46 months postoperatively.