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Pediatric Wilms Tumor (Nephroblastoma)



The rare childhood tumor of the kidney, also called nephroblastoma, may be associated with several genetic alterations and syndromes. Only about 500 cases of Wilms' tumors are diagnosed each year in the United States, mostly in children ages three to four years old.

Expanded Overview

Wilms' tumors can metastasize to the lungs and liver. Most children with a Wilms' tumor can be cured, but because the cancer is so rare, these children should be treated by specialists and considered for enrollment in a clinical trial.

Tests and Diagnosis

As we learn more about genetic predisposition to Wilms tumor, we know that some children have a much higher risk of Wilms tumor. Screening the children can detect the tumors while they are small and asymptomatic, helping to spare the kidney. Children with the following conditions usually are screened with ultrasonography every three months until age 8 for signs of Wilms tumor

  • Beckwith-Wiedemann syndrome (and other overgrowth syndromes)
  • Denys-Drash syndrome
  • Isolated hemihypertrophy
  • Sporadic aniridia
  • WAGR syndrome

Many other diseases and conditions are associated with Wilms tumors.


Symptoms can vary, but many children have:

  • Blood in the urine
  • Pain
  • Swollen abdomen or large mass in the abdomen
  • Unexplained fever

If a child has nephroblastomatosis, risk of developing a Wilms' tumor is high. The child should be monitored for at least seven years following treatment of nephroblastomatosis for signs of Wilms' tumor.

Tests and Diagnosis

A small percentage of renal masses are misdiagnosed as Wilms' tumors.  Abdominal imaging with ultrasonography, radiography and computed tomography (CT) can help detect or define a Wilms' tumor. A complete blood count, liver or renal function tests, and urinalysis can aid in differential diagnosis. Any child with a renal mass is assessed for possible associated syndromes.  


Treatment of Wilms tumors is complex. Because Wilms tumors are rare, children with the cancer should be considered for enrollment in a clinical trial when possible. 

Treatment may include nephrectomy and removal of nearby lymph nodes. If the cancer is bilateral, a partial nephrectomy is performed in one kidney to retain some renal function. Children also receive radiation therapy, chemotherapy and biologic therapy as appropriate. Children with advanced disease may require high-dose chemotherapy with a stem cell transplant or a kidney transplant.

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