A Case Study and Literature Evaluation of Primary Renal Ewing Sarcoma

Ewing’s sarcoma of the kidney (ESK) is an uncommon, aggressive soft tissue neoplasm derived from neuroectodermal tissue, specifically located in the kidney. It has an unfavorable prognosis due to its highly malignant nature, rapid progression, and swift metastasis to the lungs, bones, and lymphatic system. The precise etiology of Ewing sarcoma/primary neuroectodermal tumor (ES/PNET) remains unidentified; nevertheless, numerous studies suggest that Ewing sarcoma RNA binding protein 1 (EWSR1) may be implicated in chromosomal translocation. The condition usually manifests as radiating flank pain, and complete surgical excision is the therapeutic approach. We discuss the case of a 37-year-old Saudi woman diagnosed with primary renal Ewing sarcoma. A 37-year-old Saudi lady presenting with left flank pain, intermittent hematuria, and a palpable mass in the left upper quadrant of the abdomen was diagnosed with a small round cell tumor. Computed tomography (CT) scans identified a substantial, heterogeneous mass originating from the left kidney, accompanied by necrosis. The surgical excision of the renal tumor disclosed a sheet of small round blue cells infiltrating the renal parenchyma. Immunohistochemistry demonstrated diffuse membranous expression of CD99 and diffuse nuclear positivity for FLI1 and NKX2.2. Fluorescence in situ hybridization (FISH) confirmed EWSR1 gene rearrangement. No lymphadenopathy or metastasis was found during the initial examination. ES/PNET is an uncommon neuroectodermal soft tissue neoplasm detected via histopathological examination. Timely diagnosis is essential due to its significant invasiveness and unfavorable prognosis. Radiologists must recognize essential CT image characteristics. Multimodal therapy, comprising nephrectomy, adjuvant chemotherapy, and radiotherapy, is advised for survival.