A Case of a 15-year-old Female with Primary Renal Ewing Sarcoma.

Abstract

Ewing sarcoma is a primitive neuroectodermal tumor of bone, most commonly seen in pediatric patients. While extraskeletal Ewing sarcoma is not unheard of, some sites are more rarely seen than others.

This report describes the case of a 15-year-old female who initially presented with an abdominal mass with no associated symptoms. Initial workup and biopsy of this patient yielded a diagnosis of nephroblastoma (Wilms tumor). The tumor was surgically removed, but recurrence prompted chemotherapy for Wilms tumor. External pathologic review yielded a diagnosis of poorly differentiated renal cell carcinoma with focal papillary features. Metastatic tumors were surgically removed, while further testing of the specimens and through immunohistochemistry and molecular and genetic testing demonstrated the presence of the EWSR-FLI1 fusion gene which confirmed the diagnosis of Ewing sarcoma. The patient’s chemotherapy protocol was shifted to one specific for Ewing sarcoma. However, patient opted to discontinue treatment and expired 3 months after.

This case is interesting due to the diagnostic dilemmas that compounded the treatment of the patient. Moreover, the site of the tumor makes it an extremely rare presentation, in which only 150 cases were reported in existing literature.