Broward Urology Center physicians see a lot of people in consultation regarding “kidney cysts.” We hope this page explains the basics about kidney cysts so that you may become more knowledgeable regarding this condition. Please feel free to ask us more details during your consultation visit.
Cysts are fluid filled sacs that may occur in various parts of the body. They resemble a pimple or a boil. Certain organs tend to get cysts especially when those organs are made out of small tubes. For instance, the liver makes a fluid called bile to help you digest food and bile travels in many small tubes within the liver. The liver is very prone to cysts. Cysts are also commonly found in the testicles and organs that drain the testicles, the epididymis. Well, the kidney is made out of millions of tubes that filter blood and make urine. It is thought that some of these tubes may break and create these pockets of fluid that become a cyst.
No, kidney cysts are very common and may be found in over 50% of people over 50 years of age.
For most part, kidney cysts are a random occurrence. However, there are certain genetic conditions and medical conditions that may cause kidney cysts. A rare hereditary condition called a “polycystic kidney disease” that runs in certain families causes hundreds of cysts to form in the kidneys. Patients on chronic dialysis are also more prone to kidney cysts.
There is nothing that a person does in their life that may cause kidney cysts. No lifestyle behavior, environmental exposure or diet has been associated with kidney cysts.
Most kidney cysts are not a concern as most cysts are what we call “simple cysts”. Simple cysts are cysts that only have clear fluid inside them and do not pose any risk. In rare cases, simple cyst may be problematic if they are large and are located in an area that may be obstructing the outflow of urine from the kidney. Sometimes, simple cysts may be large enough to cause some pain.
Rarely, however, there are cysts that are actually cancerous. The way we may distinguish the benign from cancerous cysts is by way of imaging such as Kidney Ultrasound, CT scan or MRI.
On kidney ultrasound, if a cyst contains only some fluid inside of it and nothing else, it is typically a simple and benign cyst. If the cyst contains something inside besides fluid, we call these “complex cysts”.
The best way to judge whether a complex cyst is something to be concerned about is by way of CT or MRI pictures of the kidney. Once we look at those images with you, then we may be able to tell if a cyst is abnormal and judge whether the risk of a malignancy is high or low. You may hear us refer to a “Bosniak Classification” during your consultation. This is a way to categorize a cyst on a scale from 1 to 4 as to the risk of a malignancy for a particular cyst, based on how it appears on imaging.
Treatment of kidney cyst depends on the risk of malignancy. We classify this on a Bosniak scale which is basically a way to group different cysts into different categories of risk.