What is Wilms tumor?
Wilms tumor is a type of cancer in which a tumor grows on a kidney. It happens most often in children younger than 5.
Doctors don’t know what causes Wilms tumor, but children who have certain health problems at birth are more likely to get it
Children with Wilms tumor have a lump in their belly and may throw up and have belly pain, fever, poor appetite, and upset stomach
Wilms tumor usually affects one kidney, but it can affect both
Treatment includes surgery, chemotherapy, and sometimes radiation therapy
What causes Wilms tumor?
Most of the time, doctors don’t know what causes Wilms tumor. Sometimes it's caused by a problem with the child's genes.
What are the symptoms of Wilms tumor?
The first symptom of Wilms tumor is usually:
A painless lump in a child's belly
Other symptoms include:
A swollen belly (sometimes parents notice that a young child suddenly needs a larger-sized diaper)
Belly pain, fever, poor appetite, upset stomach, and throwing up
Blood in the urine
High blood pressure
If the cancer spreads to the lungs, it may cause coughing and shortness of breath.
How can doctors tell if my child has Wilms tumor?
Doctors suspect Wilms tumor if they feel a lump in a child's belly. To know for sure, they'll do:
Ultrasound, CT scan Computed Tomography A CT scan uses a large machine shaped like a large donut to take x-rays from many angles. A computer then takes the x-rays and creates many detailed pictures of the inside of your body. Each... read more
, or MRI Magnetic Resonance Imaging (MRI) MRI is a test that uses a machine with a powerful magnet to make pictures of the inside of your body. A computer records changes in the magnetic field around your body. The computer then uses... read more 
Surgery to remove the lump—doctors will look at it under a microscope to see if it's Wilms tumor
Doctors also use CT scan or MRI to see if any cancer has spread to the lymph nodes, liver, or lungs.
How do doctors treat Wilms tumor?
To treat Wilms tumor, doctors will:
During surgery, check the other kidney for cancer
In rare cases where a tumor is very large or is in both kidneys, doctors will use chemotherapy to shrink the tumor or tumors before doing surgery to remove them.
