Signs and Symptoms of Wilms Tumor

Wilms tumors can be hard to find early because they can often grow quite large without causing any symptoms. Children may look healthy and play normally.

Swelling or a hard mass in the abdomen (belly): This is often the first sign of a Wilms tumor. Parents may notice this while bathing or dressing the child. It feels firm and is often large enough to be felt on both sides of the belly. It’s usually not painful, but it might cause belly pain in some children.

Other possible symptoms: Some children with Wilms tumor may also have:

  • Fever
  • Nausea
  • Loss of appetite
  • Shortness of breath
  • Constipation
  • Blood in the urine

Wilms tumors can also sometimes cause high blood pressure. This does not usually cause symptoms on its own, but in rare cases blood pressure can get high enough to cause problems such as headaches, bleeding inside the eye, or even a change in consciousness.

Many of the signs and symptoms above are more likely to be caused by something other than a kidney tumor. Still, if your child has any of these symptoms, check with your child’s doctor so that the cause can be found and treated, if needed.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master's-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: March 6, 2015 Last Revised: February 16, 2016

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