Kidney Tumor


What is a kidney tumor?

A kidney tumor is a mass or group of abnormal cells that form on your kidney. They may be benign (not cancerous) or malignant (cancerous).

Another name for kidney tumors is renal tumors.

How serious is a tumor on your kidney?

It depends. Some kidney tumors aren’t cancerous. They’re usually smaller (less than 1.6 inches or 4 cm, about the size of a walnut) than cancerous tumors, and they won’t spread to other areas of your body.

Most large kidney tumors (greater than 1.6 inches) are malignant. They often grow quickly and may spread to other parts of your body.

Whether your kidney tumor is benign or malignant, getting treatment as soon as possible is a good idea.

Are kidney tumors usually cancerous?

About 75% of kidney tumors are cancerous. Smaller tumors aren’t usually aggressive.

How fast do kidney tumors grow?

Studies show that kidney tumors have an average growth rate of about 0.3 cm per year.

Who does a kidney tumor affect?

Anyone can get a kidney tumor. However, you’re more likely to have a kidney tumor if you’re:

  • 65 or older.
  • Male or assigned male at birth (AMAB).
  • Black, Native American, Alaskan Native or First Nation.

How common are kidney tumors?

Cancerous kidney tumors are one of the most common cancers in the United States. About 76,000 people receive a kidney cancer diagnosis each year.

Symptoms and Causes

What are the symptoms of a kidney tumor? 

Many people don’t have any pain or notice any symptoms. A healthcare provider usually discovers a kidney tumor while conducting tests for other health conditions. If you have symptoms, they usually include:

  • Blood in your pee (hematuria).
  • Pain between your ribs and hips (flank) to the touch.
  • Pain in your lower back.
  • Loss of appetite.
  • Unexplained weight loss.
  • Fever.
  • Anemia.

What causes a kidney tumor?

Healthcare providers and medical researchers don’t know the exact causes of kidney tumors. However, you may increase your likelihood of developing kidney tumors if you:

  • Use tobacco products.
  • Regularly have more than seven alcoholic drinks per week.
  • Have obesity.
  • Have a family history of high blood pressure.
  • Have a family history of kidney tumors.
  • Are regularly around chemicals that contain chlorine.

How do kidney tumors spread?

Benign kidney tumors don’t spread to other parts of your body.

Malignant kidney tumors spread from into the fat, blood vessels or adrenal gland around your kidneys. They may then spread to other areas of your body through your bloodstream or lymphatic system to form new tumors. The name of this process is metastasis.

Diagnosis and Tests

How is a kidney tumor diagnosed?

Kidney tumors usually don’t have any symptoms, so healthcare providers often discover them during tests for other conditions. If you have symptoms, a provider will conduct a complete physical examination. They’ll also ask if you have a personal or family history of kidney tumors or cancer.

They may also order tests to help diagnose kidney cancer. These tests may include the following:

  • Imaging tests. Imaging tests are painless, noninvasive tests that help your provider take a closer look at your kidneys. These tests may include a CT (computed tomography) scan, magnetic resonance imaging (MRI) scan and ultrasound.
  • Urinalysis. You’ll provide a pee sample for a healthcare provider. They’ll test your pee at a lab to see if it contains microscopic amounts of blood that aren’t visible to the naked eye.
  • Blood tests. A provider will use a thin needle to withdraw a small amount of blood. They’ll look at your blood under a microscope at a lab and count the number of each kind of blood cell, look at the different electrolytes in your body and look at creatinine levels (a byproduct of muscle activity) to see if your kidneys aren’t working as well as they should.
  • Renal mass biopsy. A provider will use a thin needle to withdraw a small sample of your kidney tumor. They’ll look at the tissue under a microscope at a lab to see if there are any cancer cells. Renal mass biopsies aren’t always reliable, so a provider may not recommend this test.

Management and Treatment

How is a kidney tumor treated?

Kidney tumor treatment depends on the size of your kidney tumor and whether it’s benign or malignant. Treatment options include:

Active surveillance

A healthcare provider may recommend active surveillance for small kidney tumors that haven’t spread to other areas of your body. The provider will pay close attention to your kidney tumor with regular screenings and imaging tests. They won’t offer treatment unless there are changes in your test results. You may get screenings or imaging tests every three months, six months or once a year while under active surveillance.


A healthcare provider may recommend surgery to remove part or all of your kidney. They may suggest several types of surgery, including:

  • Partial nephrectomy. A surgeon removes the part of your kidney that has the tumor. They leave the healthy part of your kidney intact. Providers usually recommend a partial nephrectomy if you have a small kidney tumor that hasn’t spread.
  • Radical nephrectomy. A surgeon removes your entire kidney and some of the surrounding tissue. They may also remove any lymph nodes around your kidney. Providers usually recommend a radical nephrectomy if you have a large kidney tumor near major blood vessels.

Ablation therapy

For smaller kidney tumors, a provider may recommend ablation therapy. Ablation therapy uses extreme heat or cold to destroy tumor cells. They may recommend:

  • Cryoablation. A provider inserts a needle through your skin and into the kidney tumor. They then pass a very cold gas through the needle into the tumor, which freezes and destroys the tumor cells.
  • Radiofrequency ablation. A provider inserts a needle through your skin and into the kidney tumor. They then pass an electric current through the needle into the tumor, which heats up and destroys the tumor cells.

Radiation therapy

A provider may recommend radiation therapy if you have only one kidney or can’t have surgery. It uses radiation to destroy kidney tumor cells.

Targeted drug therapy

A provider may recommend targeted drug therapy if you can’t have surgery. They may also suggest it after surgery to help prevent cancer from returning. Drugs help prevent kidney tumor cells from growing and thriving. It may also help stop the growth of new blood vessels or limit certain proteins that help cancer grow.


Immunotherapy involves medications that help your immune system do a better job of recognizing and destroying kidney tumor cells.


How can I prevent a kidney tumor?

Most kidney tumors develop for no apparent reason. However, the following tips may help reduce your risk of developing a kidney tumor:

  • Quit smoking or using tobacco products.
  • Limit the amount of alcohol you drink.
  • Exercise regularly.
  • Maintain a healthy weight for you.

Outlook / Prognosis

What can I expect if I have a kidney tumor?

Your prognosis and treatment plan depends on the size of your kidney tumor, whether it’s cancerous or noncancerous and if it has spread to other parts of your body. Your recovery also depends on your age and general health.

Can kidney tumors be cured?

With early diagnosis and proper treatment, kidney tumors are curable.

A benign kidney tumor usually isn’t life-threatening. A malignant kidney tumor is most treatable if a provider discovers it before it breaks through the outer covering of your kidney and spreads.

Living With

When should I see a healthcare provider?

Schedule an appointment with a healthcare provider if you develop symptoms of a kidney tumor, such as blood in your pee, pain in your flank or lower back and unexplained weight loss. They can conduct tests to determine if a kidney tumor is responsible for your symptoms.

What questions should I ask a healthcare provider?

  • Where is my kidney tumor?
  • Is my kidney tumor cancerous or noncancerous?
  • How big is my kidney tumor?
  • Has my kidney tumor spread to other areas of my body?
  • Do you think the kidney tumor will spread?
  • What treatment options do you recommend?
  • Will my kidney tumor come back after treatment?
  • What should I do if treatment doesn’t work?
  • Can you recommend a urologist or oncologist?
  • Can you recommend a support group for people with kidney tumors or cancer?
  • How is my kidney function after treatment?

A note from Cleveland Clinic

It can be scary and frustrating to learn that you have a kidney tumor, especially because it may be kidney cancer. Because a kidney tumor usually doesn’t have symptoms, you may not even realize you have one. However, treatment is more effective when you get an early diagnosis. A healthcare provider can explain all of your treatment options and offer additional resources. They’re also available to answer any of your questions and help you maintain a healthy outlook as you consider your treatment options.

Last reviewed by a Cleveland Clinic medical professional on 10/21/2022.


  • American Cancer Society. What Is Kidney Cancer? ( Accessed 10/21/2022.
  • Gofrit ON, Yutkin V, Zorn KC, et al. The Growth Rate of "Clinically Significant" Renal Cancer. ( Springerplus. 2015;4:580. Accessed 10/12/2022.
  • Kang SK, Bjurlin MA, Huang WC. Small Kidney Tumors. ( JAMA. 2019; 322 (6): 588. Accessed 10/21/2022.
  • National Kidney Foundation. Kidney Cancer. ( Accessed 10/21/2022.

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