A child's left arm and leg seem bigger than those on the right. In addition, the child has aniridia. None of the family members have aniridia or hemihypertrophy, nor do they know of anyone else in the family with these conditions. For each of the mentioned descriptions of a patient with a congenital anomaly, select the major abnormality with which it is most likely to be associated.

Aniridia is found in 1% to 2% of children with Wilms tumor. Genitourinary anomalies are found in 4% to 5%, and hemihypertrophy is associated with this tumor in 2% to 3% of patients. Wilms tumor is the most common primary renal malignancy in childhood. Presentation is usually an abdominal mass, sometimes with hypertension, hematuria, abdominal pain, and fever. Prognosis is generally good.