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Kidney Tumors/Wilms' Tumor

The most common kidney cancer in children is Wilms' tumor. It occurs mostly in very young children and is usually diagnosed between the ages of three and five. Approximately 500 children are diagnosed with Wilms' every year in the US. The team in our dedicated children's cancer center is very experienced in treating this disease.

Additional, but very rare kidney tumors that we treat include: renal cell carcinoma (RCC), clear cell sarcoma of the kidney (CCSK), malignant rhabdoid tumor of the kidney (MRTK), cystic nephroma, mesoblastic nephroma and renal medullary carcinoma.

What is Wilms' tumor?

Also known as nephroblastoma, Wilms' tumor most often begins before your child is even born. While the cells in the kidneys are forming, some of those cells do not mature correctly. During the first few years of life, those cells begin to rapidly reproduce, forming a tumor.

A small percentage of children with Wilms' tumors have inherited an abnormal gene from one parent. This gene greatly increases the chance that some of their kidney cells will turn into a Wilms' tumor. Some other children have certain birth defects that increase their risk for Wilms' tumor. However, many children with Wilms' tumors do not have any known inherited gene changes or birth defects. Researchers do not know why these children have some kidney cells that do not mature properly.

Click here to learn more about Wilms' tumor.

Signs and symptoms of Wilms' tumor

Your child may not have any symptoms until the tumor has become quite large and even then there may not be any other pain or symptoms. In fact, the first noticeable symptom is usually a large lump or hard mass in the abdomen. Other symptoms may include:

  • Stomach pain
  • Fever
  • Blood in the urine
  • High blood pressure
  • Loss of appetite, nausea, vomiting and constipation

Testing and diagnostics

The doctor will ask about your child's symptoms and medical history and perform a physical exam. Blood and urine tests may be done.

In addition, your child will need one or more of the tests below to look for tumors. These tests provide pictures of the kidney, surrounding blood vessels and other organs to which the cancer may have spread:

  • Ultrasound – a test that uses sound waves to examine the kidneys.
  • CT scan – a type of x-ray that uses a computer to make pictures of the inside of the body. In some cases, a dye is first injected into a vein. This dye makes structures in the body more visible on x-ray.
  • MRI scan – a test that uses magnetic waves to make pictures of the inside of the body.
  • Chest x-ray – a test that uses radiation to look for spread of cancer to the lungs.
  • Bone scan – a small amount of a radioactive material is injected into a vein to highlight any cancer that may have spread to the bones.
  • Biopsy – removal of a tissue sample to test for cancer cells. In Wilms' tumor, the biopsy may actually be a major surgical procedure to remove the kidney and nearby lymph nodes.
Child life staff
Child Life staff members help children cope with a hospital experience by providing support geared to the child's level of understanding.

Except for removal of the kidney, these tests are not invasive but do require the child to remain still. Sedation may be needed, and one of our Child Life specialists will work with your child prior to treatment and in many cases will be there to comfort your child and ease anxiety during the treatment.

Children who have risk factors for Wilms' tumor should have a physical exam with a specialist and an ultrasound every three months until age six or seven. This screening should be done even if they do not have symptoms. It can help find tumors while they are small and have not yet spread to other parts of the body.


Thanks to major innovations in the last few years, Wilms' tumor can be cured in most children. The specific treatment depends on if the cancer has spread beyond the kidney to other parts of the body, and if so, how far. The process for determining this, called staging, uses the results of the diagnostic tests. Tumor size, cell type, whether the tumor is favorable or unfavorable, and your child's age and health are also considered in choosing treatment.

In general, tumors with favorable histology and low stage are treated only with combinations of chemotherapy or under certain circumstances observation alone. Those with advanced stages, unfavorable histology or recurrent, will often require the addition of radiation therapy. Treatment may include:

  • Surgery – the main treatment for Wilms' tumor is a type of surgery called nephrectomy. This is the removal of the kidney with the tumor. The tissue around the kidney may also be removed, as well as some nearby lymph nodes. The remaining kidney will take care of all of the needed functions for the body.
  • Chemotherapy – the use of drugs to kill cancer cells. Chemotherapy can be given in many forms including: pill, injection and via a catheter placed in a blood vessel. The drugs enter the bloodstream and travel through the body killing mostly cancer cells, but also some healthy cells.
  • Radiation therapy – this is the use of radiation to kill cancer cells and shrink tumors.

We are here to help.

If your child has been diagnosed, you probably have lots of questions. We can help. If you would like to schedule an appointment, refer a patient or speak to our staff, please call our offices at 682-885-4007.