What is a Kidney Tumor?

Nicole Madison
Nicole Madison

A kidney tumor is an abnormal mass that develops in a kidney. The kidney is a bean-shaped organ that functions as part of a person's urinary system. It helps to filter waste and extra fluids from the bloodstream, creating urine, which moves to the bladder and out of the body. People are born with two kidneys.

An example of a healthy kidney and one with tumors.
An example of a healthy kidney and one with tumors.

Kidney tumors form when cells overgrow within a kidney. Usually, older cells die and are replaced by new cells. When this process goes awry, the old cells don't die off, and new cells grow when they are not needed, creating a tumor. When a tumor is benign, it is not cancerous and it does not spread to other body parts. However, tumors can sometimes impair organ function, so they may be removed surgically.

While some kidney tumors may be left alone, others may require surgical removal.
While some kidney tumors may be left alone, others may require surgical removal.

Much more serious is a malignant kidney tumor, which is cancerous and can spread to other areas in a person's body. This is potentially life threatening. Renal cell carcinoma, transitional cell carcinoma, and Wilms' tumor are the most frequently diagnosed cancerous kidney tumors. In adults, renal cell carcinoma develops most frequently. Children are more likely to develop Wilms' tumor cancer.

The kidneys perform a crucial role of keeping the blood clean and chemically balanced.
The kidneys perform a crucial role of keeping the blood clean and chemically balanced.

When a person has renal cell carcinoma, kidney tumors develop in the cells of the kidney's filtering units, which are called nephrons. Often, cancerous cells in this area grow as one mass in one kidney. However, it is possible for more than one kidney tumor to develop on just one kidney, and both kidneys can be affected by tumors at the same time.

Transitional cell carcinoma develops in the lining of the renal pelvis, which is the part of the organ responsible for collecting and draining liquid waste. Sometimes these tumors also form in the ureters, which are narrow tubes that lead to the bladder. In some cases, they even develop in the bladder itself.

Wilms' tumors form in the kidneys and can spread to lymph nodes that are near the kidneys. They may also spread to the liver and lungs. Sadly, this type of kidney tumor typically affects children who are less than five years old.

Though anyone can develop renal cell carcinoma, risk increases with age, and they are most common in those who are 60 and above. Men are more at risk than women, and smoking and obesity are also risk factors. Those who are exposed to asbestos, cadmium, and tichlorothylene may be more at risk, as are those who have been treated for kidney failure in the past. For reasons that are not fully understood, those with high blood pressure are also more at risk.

Smoking is also a risk factor for developing transitional cell carcinoma. A person is also more at risk for developing this type of kidney tumor when he works with carcinogenic chemicals in the workplace. A medication called phenacetin, which is no longer on the market in the United States, has been linked to this type of tumor as well.

People with high blood pressure are more at risk of developing a kidney tumor.
People with high blood pressure are more at risk of developing a kidney tumor.
Nicole Madison
Nicole Madison

Nicole’s thirst for knowledge inspired her to become a wiseGEEK writer, and she focuses primarily on topics such as homeschooling, parenting, health, science, and business. When not writing or spending time with her four children, Nicole enjoys reading, camping, and going to the beach.

You might also Like

Readers Also Love

Discussion Comments


I have a friend whose 17 month old son died from a kidney tumor.


@anon275196 - I am so sorry about your mother. Unfortunately, sometimes there are just no symptoms. My aunt had no symptoms for months while she had a cancer of the stomach and only discovered it when she went to the doctor for what she thought was a mild bout of food poisoning. She died a few months later.

Cancer can be completely unpredictable. I hope your mother gets all the help possible for her and that neither you nor she blame yourselves for missing something. Sometimes there's simply nothing to miss.


@anon265281 - It may or may not be cancer. A tumor can be just a benign growth, which doesn't do anything, or it could be benign (meaning it won't spread anywhere else in the body) and interfere with the kidney because it's pressing or blocking something.

Or it could be cancer, which means it will just keep growing and spreading until it is removed. I don't think there are any kidney cancer symptoms that are different from what you could get with a benign growth, so it depends on what his doctors' say after they test him.

A lesion is a kind of sore. It might indicate all kinds of things, but again, impossible to tell without tests.

I wish you and your grandfather all the best.


@anon276778 - I'm not by any means an expert, but my mother had melanoma a couple of years ago and from what I remember, if the local cancer has spread to the lymph nodes, but nowhere else, it's considered a stage three cancer.

I'm not entirely sure what that means for that kind of cancer in terms of survival odds and treatment plans, but there is a lot of information available in the internet. Just look up kidney cancer treatment.

What I do know is that most of the time, stage three cancers are quite treatable and kidney cancers are particularly so, because you can live without one kidney and getting a kidney transplant isn't as risky as, say, a heart or lung transplant.

However, again, I'm no expert. If you really want all the facts, you should talk to a doctor, particularly an expert on this kind of disease.

Good luck to you and your friend.


My best friend was just diagnosed with a tumor in his kidney, and it has spread to his lymph nodes. Is it still treatable?


My mom has a tumor on her kidney the size of her kidney. She never had blood in urine or pain in her side. The doctor figures its been there at least five years. They only found it because she needs a valve operation for her heart. She is 73 and they also found a spot on her lung.

She also needs a bone marrow biopsy for some reason. If she doesn't get one of her kidneys will be removed and within six months she'll die. But now they don't want to do her heart surgery because of the tumor and the urologist can't because she'd die because of her heart. Why did she not have blood in her urine or pain in her side?


My grandfather just found out that he has tumors in his kidneys. Does that mean it's cancer? And he has a lesion on his prostate glans. What does that mean?


@galen84basc -- The prognosis of kidney cancer depends on how advanced it is. Basically, there are four stages of kidney cancer, and the more advanced the stage is, the worse the prognosis is.

However, if the cancer is caught early, and has not moved out of the kidney, most people have oven an 80 percent chance of survival.


So what is the general prognosis for malignant kidney tumors? I know it varies from case to case, but is there a general outlook for this type of thing?


Like any kind of tumor, it is important to catch kidney tumors early.

Symptoms of kidney tumors include bloody urine (sometimes constant, sometimes periodic), a mass in the stomach, and pain in one side of the abdomen near the kidneys.

Even if you think you're just having a urinary tract infection, or recurring cramps, it's better to get yourself checked out -- kidney tumors are not something to play around with, and the sooner they are diagnosed, the better, whether they are cancerous or not.

Post your comments
Forgot password?