What You Need to Know for Your Kidney Mass Consultation With Your Urologist?
What is a kidney mass?
The most common reason that someone is found to have a kidney mass is usually by chance. Usually a patient is getting an x-ray test for something else and incidentally the radiologist (the doc who reviews the x-ray test) will comment that there is a mass.
This will usually prompt your doctor to refer you to the urologist for evaluation. There are sometimes symptoms that will prompt the evaluation for a kidney mass. Those symptoms include pain on your side and/or blood in the urine.
A kidney lesion is the term we used for a kidney mass. This is just what it sounds like, a mass or a bump on the kidney. These will come in two flavors–solid versus cystic. The difference between the two is that a kidney cyst is filled with fluid whereas a solid mass is just a chunk of tissue.
Medical terms you may hear during your appointment
Renal
The doctor may use the term renal. This is the medical term for kidney. It means the same thing. For example, instead of saying kidney mass the urologist may call it a “renal mass”.
Flank
This is the medical term describing the part of the body on the side which is between the ribs and the hip.
Cyst
There are essentially two different kinds of kidney masses. Some are solid and some are cystic. A cyst is the term we use to describe that the mass has a small outer rim and is filled with fluid.
Enhancement
One of the key features that help us determine if the mass is concerning for cancer or not is whether it enhances. This is the term that is used to compare a special measurement that the doc will do for the mass. Measurements will be taken on the x-rays before contrast dye is given and after. If there is a significant change in this measurement, then there is a higher suspicion that cancer may be present.
Benign
Benign is the term that is used to describe a mass or a sample that does not have cancer in it.
Malignant
This is the term used to describe the mass as having cancer. Physicians will use this term with cancer interchangeably.
Metastasis
This is the term used to say that the cancer has spread to other parts of the body.
Now that you are armed with the vocabulary for your appointment, let me go over what questions that you should ask or make sure are answered during your visit.
Do you think this kidney mass is a cancer?
This is basically the main question that you want to ask. You want to find out is this a mass that you should be worried about or not. If they say yes, then the follow-up question should be why. The urologist should review with you the factors that make him/her think that you have cancer. Some of those factors may include the size of the mass, whether it enhances, or if there are signs of spread (or metastasis).
Is it a cyst or a solid kidney mass?
This question gives you a better picture on what the mass actually is. It also helps you to evaluate if your urologist has actually done the proper evaluation of the mass. If it is a cyst, you should be asking what “class” the cyst is. Some kidney cysts don’t ever need a follow-up x-ray while others may need to be removed as they may contain cancer. If it is solid, then I will tell you below what makes a solid mass concerning or not.
Solid masses are more concerning for cancer than cystic masses.
What is the size of the kidney mass?
Let me tell you from a urologist perspective. Size matters. The chance of cancer rises as the mass gets bigger.
So when we are looking at an enhancing mass on a CT or MRI, I used to always tell my patients that the chance of a cancer being there is around 75-80%. Now we know that when we look at smaller masses, 2-3 cm or so, the chance of cancer goes down to like 30-50% depending on the size of the mass.
This will help guide me in recommending treatment or further testing based on the size of the mass. Additionally, if we are planning on treatment, the size and even location of the mass will be an important factor when we are considering removing the mass versus the whole kidney.
How many kidney masses do I have and which side(s) is it located on?
This again gets back to making sure the urologist has properly reviewed your imaging. Oftentimes there are other masses present but not concerning. Additionally, it’s good to know what side the problem is on so that if you ever get treatment, it is being done on the proper side.
What does it mean if a kidney mass enhances?
On a CT scan or a MRI, the key important factor that will guide the urologist about the risk of cancer is something called enchancement. When you get one of these x-rays, you will first go through the machine laying down with nothing added. This gives a baseline picture of your anatomy.
Next, the technician will put x-ray dye (or contrast) in your IV. Thankfully, for kidney mass x-rays you don’t have to drink the x-ray dye. What happens now is that the contrast rushes through your bloodstream and the organs in your body will look brighter.
If you have a kidney mass, the radiologist will take measurements during the first set of x-rays (non-contrast sequence) and compare them to measurements taken during the second set of x-rays (contrast sequence). There is a measurement called the Hounsfield unit and if these two measurements are greater than 15, we will say the kidney mass enhances and that there is a concern for cancer there. On the other hand, if we don’t see a change greater than 15 then we are reassured and will see there is no enhancement.
What is a kidney cyst?
A kidney cyst is a mass in the kidney that has a very thin wall and fills with fluid. Kidney cysts come in different shapes and sizes and there is a classification which will guide the urologist into telling you if you have a concerning kidney cyst or not. Now, overall kidney cysts are super duper common and oftentimes are nothing to worry about.
There is something called the Bosniak Classification which looks at certain features for a kidney cyst and it is this classification which will indicate how concerning a cyst may or may not be. In general, a Class I is not concerning at all and doesn’t need a follow-up x-ray. Class IV has a solid component that has the most concern for a cancer, but notably, more recent data shows that the risk of spread is lower.
Do I need any other testing for the kidney mass?
This question will get at whether or not the urologist has all the information needed to make a proper treatment choice. Some of this testing will include bloodwork. The urologist should review with you, or assess, the medical function of your kidneys.
Sometimes, certain treatments will be higher risk if you are starting with worse overall kidney function. It also will help to inform to possibility of developing kidney disease postoperatively and what changes you may need to do with your lifestyle based on that.
The other part of testing will include if all the x-rays have been performed. The urologist should complete your staging. This means that he/she should make sure there are no signs of spread as this will affect the treatment choices. Other x-rays may include a chest x-ray, bone scan, etc. Additionally, they may want a better picture of the kidney and order another CT scan, kidney ultrasound, and/or MRI.
Should we do a biopsy of the kidney mass?
This is a controversial aspect in the field. However, over time we are seeing more and more patients getting a biopsy prior to any treatment decision.
A biopsy is where a sample of the mass is taken, and a pathologist reviews it under the microscope. It is not a perfect test and the accuracy of giving the diagnosis runs in the 80-90% range.
The main risks that come with a biopsy is bleeding, injury to structures around the kidney like the intestines, blood vessels or the liver or spleen depending on the side of the body, and a biopsy not giving us a definitive answer.
There are several instances in which I will not recommend a biopsy prior to treatment. One instance is if the answer is obvious. If you have a really large, enhancing kidney mass then we already have our answer and there is no point in wasting time and effort in going through a biopsy. Another instance is when the mass is not in a good location to biopsy.
A biopsy is done by poking a needle through your side or your back. Sometimes the kidney mass is too close to a major blood vessel or a piece of intestine and as such it’s not safe to biopsy. Other times the mass is on the front of the kidney and this is not accessible through a side or back approach.
Lastly, I typically do not recommend a biopsy for a cystic kidney mass. Kidney cysts again have a very thin wall that are filled with fluid. A biopsy could rupture the cyst and even with the sample that it gets, the amount of tissue that is received is so small that it can be hard for the pathologist to interpret and give a solid answer.
Can I see the images as well as get a copy of my report?
You always are entitled to your medical results. The urologist is usually so focused on the kidneys that they will forget to disclose if the x-rays should any other important findings for you that have nothing to do with the mass.
When you look at the report, you should focus on the “Impression” section as this highlights what the radiologist found most important on your x-ray. I also like to show the images to my patient as it really helps people to understand why a certain treatment choice is being undertaken as well as why other choices aren’t.
What treatment is needed for a kidney mass?
If your urologist thinks you have kidney cancer, then I have created a post to highlight the most important factors for you to review before embarking on treatment for your kidney cancer mass. If you want a nitty gritty detailed resource for kidney cancer then the Urology Care Foundation has a good read on this topic as well.
Who is Dr. Mohammad Jafri?
I put this last section in for those of you who wanna know who I am and how I came up with this post.
I trained at Emory University in Atlanta, Georgia which is one of the premier urology programs in southeast United States. I grew up in the suburban Detroit area and decided after training to come back home to work. Currently I work at Comprehensive Urology and practice out of William Beaumont Hospital in Royal Oak, Michigan. It is here that I help train medical students and residents in the field of urology.
My passion is taking complex topics and breaking them down into simple, easy to understand concepts which is why I decided to make Urology Buddy. I hope you find this helpful and over time I will strive to grow this site and include more and more topics within my field.