Wilms tumour

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Diagnosis of Wilms tumour

Diagnosing Wilms tumour usually begins with a visit to your child’s doctor. The doctor will ask you about any symptoms your child has and do a physical exam. Based on this information, the doctor may refer you to a specialist or order tests to check for Wilms tumour or other health problems.

The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as Wilms tumour. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of Wilms tumour. If the doctor suspects Wilms tumour, your child’s care will be managed by a healthcare team that specializes in caring for children with cancer. All cases of childhood kidney tumours are considered urgent.

The following tests are commonly used to rule out or diagnose Wilms tumour. Many of the same tests used to diagnose cancer are used to find out the stage, which is how far the cancer has progressed. Your doctor may also order other tests to check your child’s general health and to help plan treatment.

Health history and physical exam

Your child’s health history is a record of symptoms, risk factors and all the medical events and problems the child has had in the past. In taking a health history, your doctor will ask questions about a family history of Wilms tumour and your child’s personal history of certain genetic conditions, including:

  • WAGR syndrome
  • Beckwith-Wiedemann syndrome
  • Denys-Drash syndrome
  • Simpson-Golabi-Behmel syndrome
  • Perlman syndrome
  • Frasier syndrome
  • Bloom syndrome

The doctor will also ask about the child’s personal history of certain congenital abnormalities, including:

  • aniridia
  • hemihypertrophy
  • undescended testicles
  • hypospadias

A physical exam allows the doctor to look for any signs of Wilms tumour. During a physical exam, the doctor may feel the abdomen for any lump or swelling. Find out more about physical exam.

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Ultrasound uses high-frequency sound waves to make images of structures in the body. It is used to look at the kidneys and surrounding structures.

An abdominal ultrasound is often the first imaging test done if the doctor suspects Wilms tumour because it is a painless procedure and it allows the doctor to see the whole abdomen.

Find out more about ultrasound.

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CT scan

A computed tomography (CT) scan uses special x-ray equipment to make 3-dimensional and cross-sectional images of organs, tissues, bones and blood vessels inside the body. A computer turns the images into detailed pictures.

An abdominal CT scan is used to look at the kidneys. A CT scan is also useful for checking whether cancer has spread to other organs or tissues, such as the other kidney, lungs, liver or brain.

Find out more about CT scan.

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Magnetic resonance imaging (MRI) uses powerful magnetic forces and radio-frequency waves to make cross-sectional images of organs, tissues, bones and blood vessels. A computer turns the images into 3-dimensional pictures.

An abdominal MRI is used to show more detailed images of the kidneys, including the major blood vessels near the kidney. MRI can also be used to check if the cancer has spread to the other kidney or the brain.

Find out more about MRI.

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Blood chemistry tests

Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can also be used to detect abnormalities. They may be used to diagnose or stage Wilms tumour.

Kidney function tests show how well the kidneys are working. Liver function tests show how well the liver is working.

Find out more about blood chemistry tests.

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A urinalysis measures substances found in the urine, such as electrolytes, hormones or other waste products of metabolism. A urinalysis may be done to see if there is blood in the urine and to check the levels of certain substances in the urine.

Find out more about urinalysis.

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In most cases of Wilms tumour, it is best to remove the primary tumour without doing a biopsy first. The most common surgery done is nephrectomy, which removes the tumour and the kidney. This surgery allows doctors to determine the extent of the disease. The surgeon will also take tissue samples from nearby lymph nodes to stage the disease and determine the best treatments to give after surgery.

A biopsy of the tumour will be done instead of surgery only if:

  • the tumour cannot be removed
  • the child only has one kidney
  • there are tumours in both kidneys

Samples collected during surgery or biopsy are tested in a lab. The report from the lab will confirm whether or not cancer cells are present in the samples.

Find out more about surgery for Wilms tumour and biopsy.

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Complete blood count

A complete blood count (CBC) measures the number and quality of white blood cells, red blood cells and platelets. A CBC is done to check for anemia, which is a low number of red blood cells.

Find out more about complete blood count (CBC).

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An x-ray uses small doses of radiation to make an image of the body’s structures on film. A chest x-ray may be done to check if the cancer has spread to the lungs.

Find out more about x-ray.

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Questions to ask your healthcare team

Find out more about preparing a child for a diagnostic test and treatment procedure. To make the decisions that are right for your child, ask the healthcare team questions about diagnosis.


The chemical processes in the body that create and use energy. It includes breaking down food and transforming it into energy, eliminating wastes and toxins, breathing, circulating blood and regulating temperature.

Metabolic means referring to or having to do with metabolism, as in metabolic rate.


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