Your kidneys remove waste products from your blood. They do this by filtering the blood and making urine. These cysts are usually small, oval or round thin-walled sacs with water in them. Usually, the cysts cause no problems. In fact, people can go through life without knowing that they have them.
Cysts can form almost anywhere in the body, but they are especially common in the kidneys.
Up to 50 percent of people older than 50 years have kidney cysts. Almost all kidney cysts are found on radiology studies, like ultrasound, CT or MRI exams that are done because of problems in other parts of the body. First, your doctor will ask if you're having any problems because of the kidney cyst. The cyst could cause pain on your side between your ribs and your hip, pain in your belly, a fever, frequent urination or blood in your urine. If you're having any of these problems, your doctor will examine you and order lab tests.