Renal Ewing sarcoma in children: a case series

: Introduction Renal Ewing Sarcoma (EWS) is a rare, malignant tumor with a poor prognosis. Its nonspecific presentation often delays diagnosis, and standardized treatment guidelines remain limited. Case Series Case 1 involved a 12-year-old girl with abdominal pain, gross hematuria, and polyuria. Symptoms persisted for 4 months despite antibiotic treatment for presumed urinary tract infection, after which a palpable right abdominal mass was detected. Imaging revealed a heterogeneous right renal mass with extensive necrosis and calcifications. Right radical nephrectomy and lymph node dissection were performed, and pathology confirmed renal EWS. She received adjuvant vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide over 7 months. At six months off treatment, the patient remained disease-free but developed renal dysfunction and hypotension. Case 2 concerned a 13-year-old girl with a history of treated abdominal group A Burkitt lymphoma. Surveillance ultrasound detected a new right renal lesion while asymptomatic. CT-guided biopsy, histopathology, and identification of an EWSR:FLI1 fusion gene confirmed renal EWS. Following 3 months of neoadjuvant chemotherapy with vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide, open radical nephrectomy was performed for local control. She experienced complications during consolidation chemotherapy, including necrotizing colitis and Clostridium septicum sepsis, and died six months after diagnosis. Conclusion Management of pediatric renal EWS should incorporate multimodal therapy centered on chemotherapy and surgical resection while carefully considering the risk of treatment-related toxicity, particularly in patients with prior chemotherapy exposure or a solitary functioning kidney.