Primary Ewing sarcoma of kidney in an elderly.

Primary Ewing sarcoma of the kidney is a very rare neoplasm that generally occurs in young adults. We report a 69-year-old woman with a history of breast cancer who on a routine annual bone scan was found to have a suspicious area over the right kidney. Computed tomography revealed a 16 by 15-cm mass that was removed by a radical nephrectomy. Pathologic examination confirmed the diagnosis of Ewing sarcoma. Three months later, the patient developed recurrence of the tumor at the nephrectomy site that significantly regressed after chemotherapy.