Small Renal Mass

A 65-year-old man with a history of well-controlled hypertension presents for a follow-up visit after an incidental finding of a small mass in the right kidney on an abdominal computed tomographic (CT) scan. (The scan had been ordered to evaluate pain in the lower quadrant, which resolved.) The mass is 3.2 cm in its largest dimension, anterior, heterogeneous, and solid, and it is in the right renal hilum near the main renal artery, vein, and ureter; the left kidney appears normal. The patient feels well, and his physical examination is unremarkable. His serum creatinine level is 1.2 mg per deciliter (106 mu mol per liter). How should this patient be further evaluated and treated?