Wilms Tumor: Symptoms, Causes, Risk Factors, Diagnosis, Stages, Types, Treatment, Complications, Prediction and Prevention

It is a rare type of kidney cancer that mainly affects children.

Wilms tumors are the most common kidney cancers in children.

Most Wilms tumors are unilateral, which means they affect only one kidney. In most cases, there is only one tumor, but 5% to 10% of children with Wilms tumors have more than one tumor in the same kidney.

About 5% of children with Wilms tumors have bilateral disease (tumors in both kidneys).

Wilms tumors often become quite large before they are noticed. Wilms tumor became the longest time the kidney in which it started. Most Wilms tumors were found before they spread ( metastasis ) to other organs.

Even if a doctor thinks a child might have cancer, like Wilms’, based on a physical exam or imaging tests, he can not be sure until a small portion of the tumor is checked in a lab.

Cancer begins when the cells of the body begin to grow out of control and multiply in the body. Cells in almost any part of the body can develop into cancer and spread to other areas of the body.

Wilms tumor, also known as nephroblastoma, is usually diagnosed in children around 3 years of age. It is rare after age 6, but it can occur in older children and adults.


Wilms tumor occurs more frequently in children with an average age of 3 to 4 years. The symptoms are similar to those of other childhood ailments, so it is important to consult your doctor to obtain an accurate diagnosis. Children with Wilms tumor can show the following symptoms:

  • Constipation .
  • Abdominal pain, swelling or discomfort.
  • Nausea and vomiting.
  • Weakness and fatigue.
  • Loss of appetite
  • Fever.
  • Blood in the urine or discoloration of the urine.
  • High blood pressure , which can cause chest pain, shortness of breath.
  • Headaches.
  • Increased and irregular growth of one side of your body.


It is unclear exactly what causes Wilms tumors. So far, researchers have found no clear link between Wilms tumor and environmental factors. These factors include medications, chemicals or infectious agents, either during a mother’s pregnancy or after birth.

Risk factor’s

Genetic factors

Researchers do not believe that children directly inherit the condition of their parents. Only one or two percent of children with Wilms tumors have a relative who has had the same condition. That relative is usually not a father.

However, researchers believe that certain genetic factors may increase a child’s risk or predispose children to develop Wilms tumor.

The following genetic syndromes may increase a child’s risk for Wilms tumor:

  • Síndrome de Beckwith-Wiedemann.
  • WAGR syndrome.
  • Denys-Drash Syndrome.
  • Frasier syndrome.
  • Perlman syndrome.
  • Sotos syndrome.
  • Simpson-Golabi-Behmel syndrome.
  • Bloom’s syndrome.
  • Li-Fraumeni syndrome.
  • Trisomy 18, also called Edward’s syndrome.

Frasier syndrome, WAGR syndrome and Denys-Drash syndrome are related to changes or mutations in the WT1 gene. Beckwith-Wiedemann syndrome, a growth disorder that causes enlargement of the body and organ, is related to a mutation in the WT2 gene.

Both are genes that suppress tumors and are found on chromosome 11. However, changes in these genes only account for a small percentage of Wilms tumors. It is likely that there are other genetic mutations that have not yet been discovered.

Children with certain birth defects may be more likely to have Wilms tumor.

The following birth defects are associated with the condition:

  • Aniridia: a missing or partially lost iris.
  • Hemihypertrophy: when one side of the body is larger than the other.
  • Cryptorchidism : testicles not descended in children.
  • Hypospadias: when the urinary opening is in the lower part of the penis.

Wilms tumor occurs a little more often in African-American children than in white children. It is less common in Asian-American children.

The risk of developing Wilms tumor may be higher in girls.


Children who have syndromes or birth defects related to Wilms tumor should be screened for the disease. These children should have a physical exam and an ultrasound regularly. The ultrasound will look for any kidney tumor before the tumor spreads to other organs.

According to the American Cancer Society, doctors recommend that children at increased risk for Wilms tumor get tested every three to four months until they are about 8 years old.

Talk to your doctor if you have a family member who has had Wilms tumor. If you do so, your doctor may recommend that all children in your family have ultrasound tests regularly.

The condition is extremely rare in children who do not have any risk factors. Therefore, tests for Wilms tumor are usually not done unless a child has symptoms, such as swelling in the abdomen.

To confirm a diagnosis of Wilms tumor, your doctor may request diagnostic tests, which include:

  • Blood or urine tests
  • Complete blood count.
  • Abdominal radiography or ultrasound.
  • Computed tomography or MRI.

These tests will help your doctor make an accurate diagnosis. Once diagnosed, more tests will be done to determine how advanced the disease is. The treatment and outlook will depend on the stage of your child’s cancer.


Wilms tumor has five stages:

  • Stage 1: The tumor is contained within a kidney and can be completely removed with surgery. About 40 to 45 percent of Wilms tumors are stage 1.
  • Stage 2: The tumor has spread to the tissue and vessels around the kidney, but it can still be completely removed with surgery. About 20 percent of Wilms tumors are stage 2.
  • Stage 3: The tumor can not be completely removed with surgery, and part of the cancer remains in the abdomen. About 20 to 25 percent of Wilms tumors are in stage 3.
  • Stage 4: The cancer has spread to distant organs, such as the lungs, liver, or brain. About 10 percent of Wilms’ tumors are in stage 4.
  • Stage 5: The tumor is in both kidneys at the time of diagnosis. About 5 percent of Wilms tumors are in stage 5.


Wilms tumors can also be classified by looking at the tumor cells with a microscope. This process is called histology.

Unfavorable histology

Unfavorable histology means that the tumors have a nucleus in the cells that looks very large and distorted. This is called anaplasia. The more anaplasia, the harder it is to cure the tumor.

Favorable histology

Favorable histology means there is no anaplasia. More than 90 percent of Wilms’ tumors have favorable histology. This means that most tumors are easier to cure.

Other types of kidney cancers in children

The majority of kidney cancers in children and Wilms tumors, but in rare cases and other types of kidney tumors.

Mesoblastic nephroma: if possible, will appear in the first months of life. Children are usually cured with surgery, but sometimes they also receive chemotherapy.

These tumors sometimes appeared shortly after treatment, so children who have had these tumors should be monitored closely during the first year after.

Clear cell kidney sarcoma: These tumors are much more likely to spread to other parts of the body than Wilms tumors, and are harder to cure. Because these tumors are rare, the treatment is often given as part of a clinical trial.

Malignant rhabdoid tumor of the kidney: these tumors occur more frequently in infants and young children. They tend to spread to other parts of the body quickly, and most have already spread by the time they are found, which makes them difficult to heal.

Renal cell carcinoma: this is the most common type of kidney cancer in adults, but it also represents a small amount of kidney tumors in children. It is rare in young children, but it is actually more common than Wilms’ tumor in older adolescents.


Since this type of cancer is so rare, children with Wilms tumors are usually treated by a team of doctors, which include:

  • Pediatricians
  • Surgeons
  • Urologists or specialists in urinary tract.
  • Oncologists or cancer specialists.

The team of doctors will develop a treatment plan for your child. Be sure to analyze all the options available to your child, as well as their possible side effects.

The main types of treatment are:

  • Surgery.
  • Chemotherapy.
  • Radiation therapy

Most children undergo a combination of treatments. Surgery is usually the first treatment used for people in the United States.

The goal of the surgery is to remove the tumor. In some cases, the tumor can not be removed because it is too large, or the cancer may have spread to both kidneys or blood vessels.

If so, your doctors may first use chemotherapy or radiation therapy (or both) to try to reduce the size of the tumor before surgery.

Your child may have to undergo more chemotherapy, radiation therapy, or surgery if the tumor is not removed completely the first time. The specific medications and the scope of the prescribed treatment will vary depending on the condition of your child.

Clinical trials

Clinical trials are research studies that test new treatments or procedures. They are an excellent way for doctors and people to learn better methods to treat cancer, especially rare cancers. Ask your doctor if a local hospital conducts clinical trials to see if you qualify.


As with any cancer, the spread of the disease to other organs or metastases is a potentially serious complication. If your child’s cancer spreads to distant organs, it will require more aggressive treatment.

Depending on the medications used for chemotherapy, your child may also experience unpleasant side effects. These vary from one child to another, but may include:

  • Hair loss.
  • Nausea and vomiting.
  • Fatigue.
  • Diarrhea.
  • Anemia.
  • Loss of appetite
  • Weightloss.
  • Pain.
  • Neutropenia.
  • Mouth ulcers
  • Hematomas.
  • Problems to sleep.
  • Bladder problems
  • Changes in the skin and nails.
  • Increased risk of infection

Talk to your doctor about what to expect during and after your child’s treatment. Your doctor may prescribe additional medications to treat the side effects of the treatment. The hair will usually grow back a few months after the treatment is completed.

The high blood pressure and kidney damage can occur as a result of their child or tumor treatment. For this reason, follow-up care is as important as initial treatment. Follow-up care may include physical exams and imaging tests to make sure the tumor has not returned.

It may also include blood and urine tests to check how the kidneys work. Ask your child’s doctor about long-term complications and how to look for these problems.

Long-term forecast

About 90% of children with Wilms tumor heal. The exact survival rate depends on the stage and the histology of the tumor. The prognosis for children with unfavorable histology is much worse than for children with favorable histology.

The four-year survival rates by tumor stage and histology are as follows:

Favorable histology

  • Stage 1: 99%.
  • Stage 2: 98%.
  • Stage 3: 94%.
  • Stage 4: 86%.
  • Stage 5: 87%.

Unfavorable histology

  • Stage 1: 83%.
  • Stage 2: 81%.
  • Stage 3: 72%.
  • Stage 4: 38%.
  • Stage 5: 55%.


Wilms tumor can not be prevented. Children with a family history of the condition or risk factors, such as birth defects or syndromes, should receive frequent kidney scans. These detection tools can ensure early detection.

Coping and support

Talk to your child’s team of doctors and specialists to get information and support. They can tell you about other support resources available while your child goes through treatment. These resources may include:

  • Social work services.
  • Advice.
  • Support groups (online or in person).
  • Financial help.
  • Advice on nutrition and diet.
  • Ask to speak with parents who have already received treatment for Wilms tumor. They can provide additional support and encouragement.

You can also contact the National Cancer Information Center of the American Cancer Society at 800-227-2345. They have on-call specialists every day, 24 hours a day, to help you and your child during and after treatment.

Your child will go through a lot during this time. You can make things a little easier for them by trying the following suggestions:

  • Stay with your child during treatment.
  • Bring a favorite toy or book with you to the hospital.
  • Take time to play while you are in the hospital, but make sure your child is getting enough rest.
  • Make sure your child is eating and drinking enough.
  • Prepare your child’s favorite foods and increase the intake of nutritional fluids if you have poor appetite.
  • Keep a diary or a record of how your child feels at home so you can share it with your doctor.
  • Discuss the illness with your child in terms they can understand and encourage your child to share their feelings.
  • Try to make life as normal as possible for them.