Nephron-Sparing Surgery for Unilateral Non-Syndromic Wilms Tumor in a 9-Day-Old Neonate.

Neonatal renal tumors are uncommon and generally associated with an excellent prognosis. We report the youngest patient to date with unilateral non-syndromic Wilms tumor successfully treated with nephron-sparing surgery rather than radical nephrectomy, which is the current standard of care. The patient subsequently received risk-adapted chemotherapy. At 18 months of follow-up, he remains asymptomatic and with symmetric differential renal volumes, consistent with preserved bilateral renal function. This case suggests that nephron-sparing surgery, when technically feasible, may represent a safe and effective treatment option for carefully selected neonatal renal tumors, offering a functional advantage over radical nephrectomy without compromising oncologic safety.