Wilms Tumor



Wilms tumor is a malignant tumor of the kidney occurring in the pediatric age group. It is also referred to as nephroblastoma.


Slightly more common in girls than boys; 90% of patients present by age 6 years


1 in 10,000 live births


  • Most common primary malignant renal tumor of childhood
  • 5–6% of all childhood cancers

Risk Factors


  • 5–10% present in the context of a predisposing syndrome
  • Familial cases represent 1–2% of cases and are more often bilateral and occur at an earlier age.
  • A tumor suppressor gene related to Wilms tumor (WT1) has been localized to chromosome 11p13. Mutations in this gene occur in 10–20% of Wilms tumors.
  • Another tumor suppressor gene, WT2, has been localized on 11p15.


  • 10–20% of Wilms tumors have a mutation in the WT1 tumor suppressor gene.
  • Causes in the remaining 80% of patients are complex and involve the WNT signaling pathway and IGF2 overexpression.

Commonly Associated Conditions

  • 12–15% of patients have other congenital anomalies.
  • May be associated with aniridia, hemihypertrophy, and cryptorchidism
  • Associated syndromes
    • WAGR (Wilms tumor, aniridia, genitourinary [GU] abnormalities, mental retardation)
    • Beckwith-Wiedemann syndrome (macroglossia, omphalocele, visceromegaly, hemihypertrophy)
    • Denys-Drash syndrome (ambiguous genitalia, progressive renal failure, and increased risk of Wilms tumor)
  • Nephroblastomatosis is a condition where islands of embryonic renal tissue develop. This is a generally benign condition which carries a risk of developing into Wilms tumor.

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