Successful bilateral nephron-sparing surgery for recurrent stage V Wilms tumor with hepatic capsule involvement: a case report.

Introduction: Wilms tumor is the Most common renal malignancy in children, but bilateral Wilms tumor (BWT) is rare and poses competing priorities for cure and renal preservation. Neoadjuvant chemotherapy followed by nephron-sparing surgery is standard, yet optimal timing when resistance emerges remains challenging. This case describes advanced BWT with secondary chemotherapy resistance and hepatic capsular involvement, successfully managed with timely, aggressive bilateral nephron-sparing surgery and liver capsule resection. Case presentation: A 5-year-old girl presented with progressive, painless abdominal distension and large, firm bilateral flank masses. Abdominal MRI showed large intrarenal tumors in both kidneys without metastases. After six months of neoadjuvant chemotherapy, initial partial response was followed by interval regrowth. She underwent single-stage bilateral nephron-sparing surgery with right partial nephrectomy plus Discussion: Bilateral Wilms tumor represents a minority of cases and carries a substantial lifetime risk of end-stage renal disease. Protocols favor neoadjuvant chemotherapy to facilitate nephron-sparing surgery within 6-12 weeks. In this patient, secondary chemotherapy resistance with predominant stromal maturation supported proceeding to surgery rather than intensifying therapy. Successful single-stage bilateral nephron-sparing surgery with negative margins avoided dialysis and transplant despite extensive bilateral disease and hepatic capsular extension. Conclusion: This case demonstrates that even in bilateral Wilms tumor complicated by secondary chemotherapy resistance and hepatic capsular involvement, aggressive nephron-sparing surgery can achieve disease control while preserving renal function. Prolonged oncologic and renal surveillance is warranted given the recognized risk of late renal events.