Tumors of the kidney and urinary tract may occur in people of any age and either sex. Many of these tumors are cancerous.

CANCER OF THE KIDNEY

Cancer of the kidney (adenocarcinoma of the kidney; renal cell carvinoma; hypernephroma) accounts for about 2 percent of cancers in adults, affecting one and a half times as many men as women. Most solid kidney tumors are cancerous, but kidney cysts (hollow, fluid-filled growths) generally aren't.

Symptoms and Diagnosis

Blood in the urine is the most common first symptom, but the amount of blood may be so small that it's detected only under a microscope. On the other hand, the urine may be visibly red. The next most common symptoms are pain in the side and a fever. Sometimes a kidney tumor is first detected when a doctor feels an enlargement or lump in the abdomen, or a tumor may be discovered incidentally during evaluation of another problem, such as high blood pressure. Blood pressure may rise because an inadequate blood supply to part or all of the kidney triggers the release of chemical messengers that elevate blood pressure. The red blood cell count may also become abrornally high, resulting in secondary polycythemia, because high levels of the hormone erythropoietin, produced by the diseased kidney, stimulate the bone marrow to increase red blood cell production.

If kidney cancer is suspected, intravenous urography, ultrasound scanning, or computed tomography (CT) may be used to visualize the tumor. Magnetic resonance imaging (MRI) may be used to provide even more information about how far the tumor has spread into nearby structures, including veins. If the tumor is hollow (a cyst), fluid may be withdrawn with a needle for analysis. X-ray studies, such as aortography and renal artery angiography, may be performed in

preparation for surgery to provide more information about the tumor and the arteries supplying it.

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