What is a Wilms' Tumor? Wilms' tumor (WT) is also known as nephroblastoma, a medical word that basically means an embryonic ("blast") tumor ("oma") of the kidney ("nephro"). It is named after Max Wilms, the physician who first described this disease. Wilms' tumor represents about 6% of all childhood cancers. Overall, it is the fourth most common tumor of childhood, and is the most common pediatric tumor of the abdomen. The tumor usually only affects one kidney (unilateral WT), but can involve both kidneys (bilateral WT) in up to 4-8% of cases. How common is Wilms' Tumor? There are just under 500 new cases of WT yearly in the United States .The rate of new cases is 8.1 for every million Caucasian children less than 15 years of age. Who gets Wilms' Tumor? As mentioned above, WT is a cancer of children, ie: a pediatric cancer. Both boys and girls can be ... read more on Wilms' Tumor: The Basics