Most of the time, kidney cancer doesn’t cause any symptoms, especially in the early stages. However, if you suddenly have a lump appear in your lower back or on your flank (your side between your ribs and your hip bone), there’s a chance it could be a sign of kidney cancer.

In this article, we’ll cover what a lump in the back due to kidney cancer is like, what causes it, and when you should talk to your doctor.

What Is a Kidney Cancer Lump Like?

A lump in the back is a lot more common in advanced kidney cancer than in the earlier stages.

People may experience a kidney cancer lump in different ways. The lump may be accompanied by side or lower back pain that can feel either dull or sharp. The lump itself may hurt, or pain may be more generalized in the area where you found the lump.

A kidney cancer lump on the flank or the back may actually stick out, or it may feel like one area is thicker or firmer than the rest of your flesh in that area. You may notice vague changes, even though you haven’t been injured in that area or know of any other reason for a change.

Other Symptoms of Kidney Cancer

A lump may be more likely to be kidney cancer if it shows up along with other symptoms of the disease. These include:

• Blood in the urine
• Tiredness and fatigue
• Fast weight loss without another explanation
• Loss of appetite
• A fever that comes and goes and isn’t caused by an infection
• Swelling, especially in your feet and ankles
• High blood pressure without another explanation

If you notice any of these other kidney cancer symptoms along with a lump in your back or flank, you should talk to your healthcare team as soon as possible. They can run some tests, identify the cause, and recommend appropriate treatment.

What Causes a Kidney Cancer Lump?

If you feel a lump on your back or your side that turns out to be kidney cancer, it’s usually because a tumor has gotten big enough that it’s pushing the skin out. It may mean that your tumor or tumors are sizable, and that you may have one of the more advanced stages of kidney cancer. Whether or not you feel a lump may depend on the type of kidney cancer you’re living with and the exact location of the tumors.

What Else Could Cause a Lump in Your Back?

Lumps in your back can have many causes besides kidney cancer. It’ll likely require seeing a doctor to figure out what’s causing yours.

You may be dealing with an episacral lipoma, where a tear in soft tissue called fascia allows a lump of fat to push through and create a bump in your skin.

It could also be a cyst along your spine, where fluid builds up in a small space in the body and creates a lump.

Lumps can also be caused by:

• Knots in the muscle
• A herniated disc
• A common fatty growth known as a lipoma
• An osteochondroma (tumor in bone and cartilage)
• An infection that has caused an abscess, or a pocket of pus, to form

All of these health conditions have different treatment options. Your healthcare provider can get you an accurate diagnosis and recommend the right way to treat it.

What Happens Next if the Doctor Suspects Kidney Cancer?

When you first talk to your doctor, they usually start by performing a physical exam to look at your whole body, including the lump. They may feel the lump specifically to see what they can learn. They may also ask about your risk factors for kidney cancer or other conditions.

If your doctors suspect kidney cancer, they’ll order some tests. They’re likely to start with blood tests and urine tests. If they see unusual cells, signs of blood in your urine, or indications that your kidneys aren’t working well, they may send you to a urologist (a specialist in urinary and kidney conditions) or an oncologist (cancer expert) who will run some more tests.

To find out if you’re living with kidney cancer, you’ll need imaging tests such as a computed tomography (CT scan), magnetic resonance imaging (MRI scan), and/or ultrasound scans.

Your healthcare team can use this information to see if there are kidney tumors, whether they appear benign (harmless) or cancerous, how large they are, and where they’re located. They may also be able to see if kidney cancer has spread anywhere near the kidney.

If your doctors need more information before they decide on a treatment plan, they may order a biopsy in selected cases, particularly if the diagnosis is uncertain or before nonsurgical treatment is planned. In this procedure, they use a long needle to take a sample of your kidney tissue. Then, they send that sample to a lab where it can be examined under a microscope and tested.

Your doctor will use information from all of the tests you have to decide whether you have kidney cancer. Your cancer care team can also use this information to tell you more about what stage and grade of kidney cancer you’re dealing with, which can influence your cancer treatment plan and your overall prognosis.

When To Talk to Your Doctor About Lumps

Deciding whether or not to talk to a doctor about a lump in your back or your side can be difficult. Many people don’t want the hassle of a medical appointment for something that isn’t a big deal, but they also don’t want to miss something major.

In general, if you feel a lump anywhere in your abdomen, you should talk to your doctor about it. If that lump comes alongside other symptoms of kidney cancer, you should have this conversation as soon as you can.

You should also have a lump checked out if:

• It feels hard, not soft or squishy, when you touch it
• It’s hot, itchy, or bleeding
• The skin on or around the lump is discolored
• It’s getting bigger
• It has an outline that’s irregular or not symmetrical
• It’s painful when you touch it
• The skin around the lump looks like an orange peel or seems puckered

These are all signs that the lump may be something serious and require medical attention. Your doctor should be able to tell you more after they see and examine the lump for themselves.

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On MyKidneyCancerTeam, people share their experiences with kidney cancer, get advice, and find support from others who understand.

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