Thankfully, cancer of the kidney in children is rare. However, there are some cancerous tumors of the kidney that can present in children. These tend to be different types of cancer than those that cause cancer of the kidney in older adults. Symptoms can include an abdominal mass, bloody urine, recurring unexplained fevers, unintentional weight loss (in older kids/teens) or failure to thrive (unable to grow and gain weight normally) in younger children. Some kidney cancers in children present as part of genetic syndromes, while others occur sporadically. Although there are many types of malignant tumors of the kidney in children, those seen most commonly by a urologist include Wilms’ tumors and neuroblastomas. Diagnostic tests usually involve a combination of blood and urine tests, imaging studies and sometimes specialized tests ordered and performed by a childhood cancer specialist (oncologist). In many cases, surgery has an important initial role in treating many childhood cancers that involve the kidney. Treatment of these conditions usually involves the coordination of many specialists, including pediatric urologists, to deliver the best care and outcomes possible for these children.