Epidemiology

  • Peak incidence: between 2 and 5 years
  • Most common malignant neoplasm of the kidney in children

Etiology

Can be associated with loss-of-function mutations of tumor suppressor genes WT1 or WT2 on chromosome 11 (W11ms tumor).

Associated syndromes

  • WAGR syndrome: Deletion of the 11p13 band leads to the deletion of the WT1 gene and other genes, such as PAX6.
    • Nephroblastoma
    • Aniridia
    • Genitourinary anomalies
      • Pseudohermaphroditism, undescended testes in males (due to gonadal dysgenesis)
      • Early-onset nephrotic syndrome
    • Range of intellectual disability
  • Denys-Drash syndrome: a mild form of WAGR without aniridia or intellectual disability.
    • Nephroblastoma
    • Pseudohermaphroditism, undescended testes in males (due to gonadal dysgenesis)
    • Early-onset nephrotic syndrome caused by diffuse mesangial sclerosis
  • Beckwith-Wiedemann syndrome: mutations of the WT2 gene

Pathophysiology


Clinical features

Abdominal symptoms

  • Palpable abdominal mass (often found incidentally)
    • Non-tender
    • Unilateral and large but not crossing midline
    • Smooth and firm
  • Abdominal pain (∼ 40% of cases)

Other signs and symptoms

  • Hematuria (∼ 25% of cases)
  • Hypertension (∼ 25% of cases)

Tip

Nephroblastoma should be suspected in a toddler with a non-tender abdominal mass, especially if it is firm, smooth, and associated with hematuria and/or hypertension.

Warning

Careless palpation of a nephroblastoma can result in rupture of the renal capsule and tumor spillage!


Diagnostics


Treatment

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