A 40-year-old male complains of hematuria and an aching pain in his flank. Laboratory data show normal BUN, creatinine, and electrolytes. Hemoglobin is elevated at 18 g/dL and serum calcium is 11 mg/dL. A solid renal mass is found by ultrasound. The most likely diagnosis is
Polycystic kidney disease
Renal carcinoma
Adrenal adenoma
Urolithiasis
Renal carcinoma is twice as common in men as women and tends to occur in the 50- to 70-year age group. Many patients present with a hematuria or flank pain, but the classic triad of hematuria, flank pain, and a palpable flank mass occurs in only 10 to 20% of patients. Paraneoplastic syndromes such as erythrocytosis, hypercalcemia, hepatic dysfunction, and fever of unknown origin are common. Surgery is the only potentially curable therapy; the results of treatment with chemotherapy or radiation therapy for nonresectable disease have been disappointing. Interferon a and interleukin 2 produce responses (but no cures) in 10 to 20% of patients. The prognosis for metastatic renal cell carcinoma is dismal.