Definition

Wilms' tumor is a cancerous tumor of the kidney that usually occurs in young children.

Description

When an unborn baby is developing, the kidneys are formed from primitive cells. Over time, these cells become more specialized. The cells mature and organize into the normal kidney structure. Sometimes, clumps of these cells remain in their original, primitive form. If these more primitive cells begin to multiply after birth, they may ultimately form a large mass of abnormal cells. This is known as a Wilms' tumor. Wilms' tumor may occur in only one or in both kidneys. About 7 percent of all cases of Wilms' tumor occur bilaterally (in both kidneys simultaneously).

Wilms' tumor is a type of malignant tumor. This means that it is made up of cells that are significantly...