An unusual case of renal Ewing sarcoma: A case report and review of literature

• Renal EWS is rare, with aggressive clinical progression, early metastasis and poor prognosis. • Combination of histological and immunohistochemical evaluation is important for the diagnosis. • Renal mass with vessel and/or spinal invasion should raise suspicion for renal EWS. In this report, we present a rare case of renal EWS in a 47-year- old man who presented with complaints of hematuria and flank pain. On CT imaging a 7 cm lobulated mass was discovered. Suspecting malignancy, a radical nephrectomy was performed. Microscopic evaluation showed features consistent with a small round blue cell sarcoma. Immunohistochemical stains and FISH with positive EWSR1 translocation confirmed the diagnosis. An extensive review of literature in English language returned under 150 reports of renal EWS making it a rare entity with many differentials like rhabdomyosarcoma, neuroblastoma and desmoplastic small round cell tumor.