Wilms tumor

Alternative Names

Nephroblastoma; Kidney tumor

Definition of Wilms tumor

Wilms tumor is a type of kidney cancer that occurs in children.

Causes, incidence, and risk factors

Wilms tumor is the most common form of childhood kidney cancer. The exact cause of this tumor in most children is unknown.

Signs and tests

Special emphasis is placed on the history and physical exam. The doctor may ask if you have a family history of cancer and look for associated birth defects in the child.


If your child is diagnosed with this condition, avoid prodding or pushing on the child’s belly area, and use care during bathing and handling to avoid injury to the tumor site.

Expectations (prognosis)

Children whose tumor has not spread have a 90% cure rate with appropriate treatment.


Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine; Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 6/7/2010

Kidney anatomy
Wilms tumor

ADAM Medical Encyclopedia

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