Wilms Tumor - Childhood: Symptoms and Signs

Approved by the Cancer.Net Editorial Board, 07/2023

ON THIS PAGE: You will find out more about the changes and medical problems that can be a sign of a Wilms tumor. Use the menu to see other pages.

What are the symptoms and signs of a Wilms tumor?

Children with a Wilms tumor may experience one or more of the following symptoms or signs. Symptoms are changes that you can feel in your body. Signs are changes in something measured, like taking your blood pressure or doing a lab test. Together, symptoms and signs can help describe a medical problem. Sometimes, children with a Wilms tumor do not have any of the symptoms and signs described below. Or, the cause of a symptom or sign may be a medical condition that is not cancer.

Usually, a Wilms tumor is found before it spreads to other parts of the body. A parent or relative may notice a large lump or feel a hard mass in the child’s belly or notice that the belly is much larger than usual. In some cases, a rapid change to a larger diaper size alerts parents to the presence of a tumor. A few children have abdominal pain. However, most of the time, the tumor grows without causing pain, and the child feels and appears healthy.

Frequently, children with a Wilms tumor may have the following symptoms:

  • Blood in the urine

  • High blood pressure

  • Anemia, which is a low level of red blood cells

  • Fatigue

  • A fever that does not go away

If you are concerned about any changes your child experiences, please talk with your child’s doctor. Your doctor will try to understand what is causing your child’s symptom(s). They may do an exam and order tests to understand the cause of the problem, which is called a diagnosis.

If a Wilms tumor is diagnosed, relieving symptoms remains an important part of your child’s cancer care and treatment. Managing symptoms may also be called "palliative and supportive care," which is not the same as hospice care given at the end of life. This type of care focuses on managing symptoms and supporting people who face serious illnesses, such as cancer. You can receive palliative and supportive care at any time during cancer treatment. Learn more in this guide’s section on Coping with Treatment.

Be sure to talk with your child’s health care team about the symptoms your child experiences, including any new symptoms or a change in symptoms.

The next section in this guide is Diagnosis. It explains what tests may be needed to learn more about the cause of the symptoms. Use the menu to choose a different section to read in this guide.