Final answer:
A 2-year-old child with hypertension and an asymptomatic abdominal mass is most likely dealing with a Wilms tumor. The best tests for confirmation would be a renal ultrasound and a CT scan.
Step-by-step explanation:
In a 2-year-old child with hypertension and an asymptomatic abdominal mass, the most likely diagnosis is a Wilms tumor (also known as a nephroblastoma). Wilms tumor is the most common childhood renal tumor and is often associated with WAGR syndrome and Denys-Drash syndrome. The best test to confirm the diagnosis is a renal ultrasound and a CT scan. Treatment typically involves a combination of surgery, radiation therapy, and chemotherapy.