RESUMEN
Introduction: Nephroblastoma, or Wilms' tumor, is a malignant renal neoplasm commonly found in children, is extremely rare in adults representing only 0.5% of all renal neoplasms. Adult Wilms tumor is rare, to our knowledge fewer than 300 cases have been reported in the English literature to date. However, in older adults after 60 years of age, only less than 45 cases have been reported. For this reason, treatment guidelines in adults still are lacking. Prognosis in nephroblastoma for adult patients is found to be worse than in children. Case Presentation: We report the case of a 65-year-old female with lumbar fossa mass, flank pain and hematuria, and pathologic diagnosis of Wilms tumor. We performed nephrectomy. No adjuvant treatment was given. Our patient remains asymptomatic and without evidence of recurrence 12 months after the surgery. Conclusion: Nephroblastoma in the elderly presents different clinical behavior and prognosis compared to nephroblastoma in children.