Wilms' tumor is most frequently detected in children between the ages of two and three, though it can occur in infants as well as adults. Typically, the tumor is initially detected as a lump in the abdomen, usually found by a parent or a pediatrician during a routine check-up. The tumor usually grows without any accompanying pain, and a child with Wilms' tumor may feel and appear healthy. Although in about one quarter of children, it is accompanied by such symptoms as blood in the urine, anemia, malaise, weight loss, and fever.
