Virginia Commonwealth University

VCU Massey Cancer Center

What is Wilms tumor?

Wilms tumor, also called nephroblastoma, is a malignant (cancerous) tumor originating in the cells of the kidney. It is the most common type of renal (kidney) cancer and accounts for about 6 percent of all childhood cancers.

Approximately 500 children in the U.S. are diagnosed with Wilms tumor each year.

The disease can occur at any age between infancy and 15 years, but, in most cases, the tumor is detected by the age of 3. This cancer affects males and females equally.

The tumor can be very large and it may spread (metastasize) to other body tissues. The most common site for Wilms tumor to metastasize is the lungs. Lesions also may occur, however, in the liver, the other kidney, brain and/or bones. In approximately 5 percent to 10 percent of children with Wilms tumor, both kidneys are involved.