A 60-year-old man presents with dull aching pain in the right flank. Physical examination reveals a firm mass that does not move with inspiration. Laboratory studies show normal BUN, creatinine, and electrolytes. UA shows hematuria. Hemoglobin is elevated at 18 g/dL and serum calcium is 11 mg/dL.
What is the most likely diagnosis?
A. Polycystic kidney diseaseRenal cell 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 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-alpha and interleukin-2 produce responses (but no cures) in 10% to 20% of patients. Newer tyrosine kinase inhibitors (eg, sunitinib) are active against renal cell cancers and hold promise for more effective treatment. The prognosis for metastatic renal cell carcinoma is dismal. Pheochromocytoma can cause erythrocytosis and occasionally hypercalcemia but would not cause hematuria or an intrarenal mass. Polycystic kidney disease can cause erythrocytosis because of erythropoietin production by the cysts but would cause numerous bilateral cysts, not a solid mass. Renal adenomyolipoma is a benign tumor that can present as a solitary renal mass on ultrasound. It has a characteristic CT appearance due to fat in the tumor. Neither renal adenomyolipoma nor adrenal carcinoma would cause erythrocytosis or hypercalcemia.