Nephroblastoma, also known as Wilms tumor, is a type of kidney cancer that primarily affects children, typically between the ages of 3 and 4. It arises from immature kidney cells and is usually found in one kidney, although it can occur in both. Symptoms may include abdominal swelling, pain, fever, and blood in the urine. The exact cause of nephroblastoma is not fully understood, but certain genetic conditions, such as WAGR syndrome and Denys-Drash syndrome, can increase the risk. Treatment often involves a combination of surgery, chemotherapy, and sometimes radiation therapy, with a generally favorable prognosis when detected early.