Signs and symptoms of Wilms' tumor vary widely, and some children don't show any obvious signs. But most children with Wilms' tumor experience one or more of these signs and symptoms: 
An abdominal mass you can feel
Abdominal swelling
Abdominal pain
 Other signs and symptoms may include: 
Fever
Blood in the urine
Nausea or vomiting or both
Constipation
Loss of appetite
Shortness of breath
High blood pressure
