Most kidney tumors are found incidentally — during an evaluation with radiologic imaging studies for other nonspecific abdominal complaints (gallbladder pain, for example), or during follow-up for other previously treated malignancies. These “incidental cancers” are often found early, before any symptoms have occurred. Because such cancers are usually detected before they have spread, patients with incidental kidney tumors are often cured of their disease, commonly by surgery alone.

Moreover, as many as 30 percent of kidney masses represent a benign condition. Often, Memorial Sloan Kettering doctors repeat radiologic imaging done at another institution to diagnose a benign mass, avoiding the need for a biopsy or surgical intervention.

If your doctor suspects you have a kidney tumor, he or she may recommend computed tomography (CT) scanning or magnetic resonance imaging (MRI). Recently developed imaging techniques — including 3-D CT, 3-D MRI angiography (imaging of the blood vessels), and CT urography (imaging of part of the urinary tract) — reveal detailed anatomy, which allows the doctor to plan surgery, often using a single imaging test. Ultrasound may be used when it is necessary to determine whether a kidney mass is a fluid-filled cyst or a solid tumor. To limit the radiation exposure to our patients as much as possible, we make every attempt to perform CT scans only when absolutely necessary.

If your doctor suspects that you have cancer of the renal pelvis, or transitional cell carcinoma, he or she may perform one of the following:

  • Cytoscopy, which involves inserting a small tube with a lens into the urethra to allow the bladder and urethra to be seen;
  • Pyelogram, which involves taking an x-ray of the kidneys and ureters.
  • Ureteroscopy, which involves passing a narrow lighted tube through the urethra, into the bladder, into a ureter, and into the renal pelvis to look for signs of cancer.

Your doctor may remove a small piece of tissue (a biopsy) to examine it for cancer cells.

After surgery to remove a renal cortical tumor, pathologists will examine the tumor cells to determine if the tumor is benign or malignant. If it is cancerous, they will determine which cell type is present. Our doctors then use this information, along with the size of the tumor and other aspects of the tumor’s growth, to more accurately predict the prognosis and determine whether further treatment is necessary.

In addition to these tests, when making treatment decisions your doctor will take your medical history into account, perform a physical examination, and order laboratory studies such as blood and urine tests.