Wilms' tumor is a cancer that affects the kidneys and can progress throughout the body, explains the American Cancer Society. The condition, also known as nephroblastoma, was named after a German doctor who published early research on the illness.
Wilms' tumor is the most common type of kidney cancer that affects children, according to the American Cancer Society. Most children are diagnosed with Wilms' tumors that only affect one kidney. Approximately 5 percent of children diagnosed with this condition have tumors in both kidneys. The tumors often progress to a large size before they are noticed and can grow larger than the kidney itself.
Two major types of Wilms' tumors can be detected under a microscope by medical professionals, explains the American Cancer Society. Favorable histology is the most common type of Wilms' tumors, and the cure rate is high for children with this type of Wilms' tumor. Patients with unfavorable histology or an anaplastic Wilms' tumor possess cancer cells that are distorted and large. This type of kidney cancer is often more difficult to cure.
A Wilms' tumor can metastasize or spread to other organs in the body, causing cancer to spread beyond the kidneys, according to the American Cancer Society.