Which renal tumor is most commonly diagnosed in children, with a mean age of 3.5 years?

Wilm's tumor, also known as nephroblastoma, is the most commonly diagnosed renal tumor in children, typically arising between the ages of 1 and 5 years, with a mean age of diagnosis around 3.5 years. This tumor originates from immature kidney cells and is often associated with specific genetic syndromes, such as WAGR syndrome and Beckwith-Wiedemann syndrome.

The presentation of Wilm's tumor usually includes an abdominal mass, which can sometimes be palpable during a physical examination. Other clinical features may include hematuria, hypertension, or abdominal pain. Early detection and treatment are crucial for a favorable outcome, as Wilm's tumor is highly responsive to chemotherapy and surgery.

In comparison, although neuroblastoma can also occur in young children, it primarily originates from neural crest cells rather than kidney tissue. Hepatoblastoma originates in the liver, predominantly affecting infants and young children as well. Rhabdomyosarcoma, while it can present in various locations throughout the body, is a soft tissue sarcoma that does not specifically arise from the kidney. Therefore, Wilm's tumor clearly stands out as the most prevalent renal tumor in pediatric patients.