Wilms Tumor

Wilms tumor is a kidney tumor found almost always in children. This condition represents nearly 90% of kidney tumors in children. In some cases, Wilms tumor is part of a group of conditions that are present at birth. These are called congenital syndromes.

Wilms tumor is also called Wilms’ tumor or nephroblastoma. Usually, there is only one tumor on one kidney, but there can sometimes be tumors on both kidneys (bilateral) or more than one cancerous spot on one kidney.

Who does Wilms tumor affect?

Although there’ve been rare cases in adults, Wilms tumor is a cancer found mostly in children under 15 years old. About 95% of cases of this disease are diagnosed by the time a child is 10 years old.

The risk is higher in Black children and lower in Asian children. Wilms tumor is a little bit more common in girls than boys.

Wilms tumor has been passed down in the genes of a very small percentage of families.

How common is this condition?

There are an estimated 500 new cases of Wilms tumor diagnosed in the U.S. every year.

What types of congenital (present at birth) syndromes are often found with Wilms tumor?

Very rarely, people with Wilms tumor also have other congenital syndromes. Some of these syndromes include:

• Beckwith-Wiedemann syndrome: Children with this syndrome have a 5% to 10% risk of developing Wilms. This syndrome is classified as an overgrowth syndrome — body parts grow larger and one side of the body doesn’t always match the other side.
• WAGR syndrome: Children with this syndrome have about a 50% chance of developing Wilms tumor. (The “W” in the name stands for Wilms.) Other complications include lack of an iris in the eye (Aniridia) and Genital or the Renal issues.
• Denys-Drash syndrome (also known as Drash syndrome): Children with this grouping of medical conditions have a 90% chance of developing Wilms. Other issues involve their genitals and kidneys.