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Wilms Tumor and Other Childhood Kidney Tumors Treatment (PDQ®)

General Information About Wilms Tumor and Other Childhood Kidney Tumors

Childhood kidney tumors are diseases in which malignant (cancer) cells form in the tissues of the kidney.

There are two kidneys, one on each side of the backbone, above the waist. Tiny tubules in the kidneys filter and clean the blood. They take out waste products and make urine. The urine passes from each kidney through a long tube called a ureter into the bladder. The bladder holds the urine until it passes through the urethra and leaves the body.

Anatomy of the female urinary system; drawing shows a front view of the right and left kidneys, the ureters, urethra, and bladder filled with urine. The inside of the left kidney shows the renal pelvis. An inset shows the renal tubules and urine. The spine, adrenal glands, and uterus are also shown.
Anatomy of the female urinary system showing the kidneys, adrenal glands, ureters, bladder, and urethra. Urine is made in the renal tubules and collects in the renal pelvis of each kidney. The urine flows from the kidneys through the ureters to the bladder. The urine is stored in the bladder until it leaves the body through the urethra.


There are many types of childhood kidney tumors.

Wilms Tumor

In Wilms tumor, one or more tumors may be found in one or both kidneys. Wilms tumor may spread to the lungs, liver, bone, brain, or nearby lymph nodes. Most childhood kidney cancers are Wilms tumors, but in children 15 to 19 years old, renal cell cancer is more common.

Renal Cell Cancer (RCC)

Renal cell cancer is rare in children and adolescents younger than 15 years old. It is much more common in adolescents between 15 and 19 years old. Renal cell cancers may spread to the lungs, liver, or lymph nodes. Renal cell cancer may also be called renal cell carcinoma.

Rhabdoid Tumor of the Kidney

Rhabdoid tumor of the kidney is a type of kidney cancer that occurs mostly in infants and young children. It is often advanced at the time of diagnosis. Rhabdoid tumor of the kidney grows and spreads quickly, often to the lungs or brain.

Children with a certain gene change are checked regularly to see if a rhabdoid tumor has formed in the kidney or has spread to the brain:

  • Children younger than one year old have an ultrasound of the abdomen every two to three months and an ultrasound of the brain every month.
  • Children one to four years old have an ultrasound of the abdomen and an MRI of the brain and spine every three months.

Clear Cell Sarcoma of the Kidney

Clear cell sarcoma of the kidney is a type of kidney tumor that may spread to the lung, bone, brain, or soft tissue. When it recurs (comes back) after treatment, it often recurs in the brain.

Congenital Mesoblastic Nephroma

Congenital mesoblastic nephroma is a tumor of the kidney that is often diagnosed during the first year of life. It can usually be cured.

Ewing Sarcoma (Neuroepithelial Tumor) of the Kidney

Ewing sarcoma (neuroepithelial tumor) of the kidney is rare and usually occurs in young adults. These tumors grow and spread to other parts of the body quickly.

Desmoplastic Small Round Cell Tumor of the Kidney

Desmoplastic small round cell tumor of the kidney is a rare soft tissue sarcoma. See the PDQ summary about Childhood Soft Tissue Sarcoma Treatment for more information.

Cystic Partially Differentiated Nephroblastoma

Cystic partially differentiated nephroblastoma is a very rare type of Wilms tumor made up of cysts.

Multilocular Cystic Nephroma

Multilocular cystic nephromas are benign tumors made up of cysts. These tumors can occur in one or both kidneys. Children with this type of tumor also may have pleuropulmonary blastomas, so imaging tests of the chest are done. See the PDQ summary about Unusual Cancers of Childhood Treatment for more information.

Primary Renal Synovial Sarcoma

Primary renal synovial sarcoma is a rare tumor of the kidney and is most common in young adults. These tumors grow and spread quickly.

Anaplastic Sarcoma of the Kidney

Anaplastic sarcoma of the kidney is a rare tumor that is most common in children or adolescents younger than 15 years of age. Anaplastic sarcoma of the kidney often spreads to the lungs, liver, or bones.

Nephroblastomatosis is not cancer but may become Wilms tumor.

Sometimes, after the kidneys form in the fetus, abnormal groups of kidney cells remain in one or both kidneys. In nephroblastomatosis, these abnormal groups of cells may grow in many places inside the kidney or make a thick layer around the kidney. When these groups of abnormal cells are found in a kidney that was removed for Wilms tumor, the child has an increased risk of Wilms tumor in the other kidney. Frequent follow-up testing is important for at least 7 years after the child is treated.

Having certain genetic syndromes or other conditions can increase the risk of Wilms tumor.

Anything that increases the risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your child's doctor if you think your child may be at risk.

Wilms tumor may be part of a genetic syndrome that affects growth or development. A genetic syndrome is a set of signs and symptoms or conditions that occur together and is caused by certain changes in the genes. Certain conditions can also increase a child's risk of developing Wilms tumor. These and other genetic syndromes and conditions have been linked to Wilms tumor:

Tests are used to screen for Wilms tumor.

Screening tests are done in children with an increased risk of Wilms tumor. These tests may help find cancer early and decrease the chance of dying from cancer.

In general, children with an increased risk of Wilms tumor should be screened for Wilms tumor every three months until they are at least 8 years old. An ultrasound test of the abdomen is usually used for screening. Small Wilms tumors may be found early and removed.

Children with Beckwith-Wiedemann syndrome or hemihypertrophy are also screened for liver and adrenal tumors that are linked to these genetic syndromes. A test to check the alpha-fetoprotein (AFP) level in the blood and an ultrasound of the abdomen are done until the child is 4 years old. An ultrasound of the kidneys is done after the child is 4 years old.

Children with aniridia and a certain gene change are screened for Wilms tumor every three months until they are 8 years old. An ultrasound test of the abdomen is used for screening.

Some children develop Wilms tumor in both kidneys. These often appear when Wilms tumor is first diagnosed, but Wilms tumor may also occur in the second kidney after the child is successfully treated for Wilms tumor in one kidney. A second tumor is much more likely to develop in the other kidney when a child's first Wilms tumor is diagnosed before they are one year old or when embryonic cells remain in the kidney. Children with an increased risk of a second Wilms tumor in the other kidney should be screened for Wilms tumor every three months for two to six years. An ultrasound test of the abdomen may be used for screening.

Having certain conditions may increase the risk of renal cell cancer.

Renal cell cancer may be related to the following conditions:

  • Von Hippel-Lindau disease (an inherited condition that causes abnormal growth of blood vessels). Children with Von Hippel-Lindau disease should be checked yearly for renal cell cancer with an ultrasound of the abdomen or an MRI (magnetic resonance imaging) beginning at age 8 to 11 years.
  • Tuberous sclerosis (an inherited disease marked by noncancerous fatty cysts in the kidney).
  • Familial renal cell cancer (an inherited condition that occurs when certain changes in the genes that cause kidney cancer are passed down from the parent to the child).
  • Renal medullary cancer (a rare kidney cancer that grows and spreads quickly).
  • Hereditary leiomyomatosis (an inherited disorder that increases the risk of having cancer of the kidney, skin, and uterus).
  • Second cancers (renal cell cancer may occur several years after treatment for neuroblastoma).

Treatment for Wilms tumor and other childhood kidney tumors may include genetic counseling.

Genetic counseling (a discussion with a trained professional about genetic diseases and whether genetic testing is needed) may be needed if the child has one of the following syndromes or conditions:

Signs of Wilms tumor and other childhood kidney tumors include a lump in the abdomen and blood in the urine.

These and other signs and symptoms may be caused by kidney tumors or by other conditions. Check with your child's doctor if your child has any of the following:

  • A lump, swelling, or pain in the abdomen.
  • Blood in the urine.
  • Fever for no known reason.
  • High blood pressure (headache, feeling very tired, chest pain, or trouble seeing or breathing).
  • Hypercalcemia (loss of appetite, nausea and vomiting, weakness, or feeling very tired).

Wilms tumor that has spread to the lungs or liver may cause the following signs and symptoms:

  • Cough.
  • Blood in the sputum.
  • Trouble breathing.
  • Pain in the abdomen.

Tests that examine the kidney and the blood are used to detect (find) and diagnose Wilms tumor and other childhood kidney tumors.

The following tests and procedures may be used:

  • Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
  • Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following:
  • Blood chemistry studies : A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. This test is done to check how well the liver and kidneys are working.
  • Renal function test : A procedure in which blood or urine samples are checked to measure the amounts of certain substances released into the blood or urine by the kidneys. A higher or lower than normal amount of a substance can be a sign that the kidneys are not working as they should.
  • Urinalysis : A test to check the color of urine and its contents, such as sugar, protein, blood, and bacteria.
  • Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. An ultrasound of the abdomen is done to diagnose a kidney tumor.
  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the chest, abdomen, and pelvis, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
  • MRI (magnetic resonance imaging) with gadolinium: A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the abdomen. A substance called gadolinium is injected into a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).
  • X-ray of the abdomen: An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
  • PET-CT scan : A procedure that combines the pictures from a positron emission tomography (PET) scan and a computed tomography (CT) scan. The PET and CT scans are done at the same time on the same machine. The pictures from both scans are combined to make a more detailed picture than either test would make by itself. A PET scan is a procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
  • Biopsy : The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. The decision to do a biopsy is based on one or more of the following:
    • The size of the tumor.
    • The stage of the cancer.
    • Whether cancer is in one or both kidneys.
    • Whether imaging tests clearly show the cancer.
    • Whether the tumor can be removed by surgery.
    • Whether the patient is in a clinical trial.
    A biopsy may be done before any treatment is given, after chemotherapy to shrink the tumor, or after surgery to remove the tumor.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options for Wilms tumor depend on the following:

  • How different the tumor cells are from normal kidney cells when looked at under a microscope.
  • The stage of the cancer.
  • The type and size of the tumor.
  • The age of the child.
  • Whether the tumor can be completely removed by surgery.
  • Whether there are certain changes in chromosomes or genes.
  • Whether the cancer has just been diagnosed or has recurred (come back).

The prognosis for renal cell cancer depends on the following:

  • The stage of the cancer.

The prognosis for rhabdoid tumor of the kidney depends on the following:

  • The age of the child when cancer is diagnosed.
  • The stage of the cancer.
  • Whether the cancer has spread to the brain.

The prognosis for clear cell sarcoma of the kidney depends on the following:

  • The age of the child when cancer is diagnosed.
  • The stage of the cancer.

Wilms tumor is rare in adults.

Wilms tumor in adults is harder to cure than in children.

  • Updated: October 30, 2014