Ewing sarcoma/peripheral primitive neuroectodermal tumor of the kidney: report of two cases

Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) arising in the kidney is very rare, and only a few cases have been reported. Here we present two cases of renal ES/pPNET with different prognosis. Both patients underwent radical nephrectomy. One patient had complex EWSR1 gene chromosome translocation, high Ki-67 proliferative index and died of metastatic disease 2 months after surgery. The other patient had conventional EWSR1 gene translocation, low Ki-67 proliferative index and is alive with no evidence of disease after 4 year follow-up.National Natural Science Foundation of China [81272945]; Beijing Natural Science Foundation of China [7122100]SCI(E)ARTICLEhxwanghua@aliyun.com34073-4077