Acquired cysts usually do not cause symptoms or affect kidney function. People may develop a single cyst or many cysts in one or both kidneys.
The cause of single cysts and usually of multiple cysts is unknown. However, multiple cysts are more common in people with chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more , especially people undergoing dialysis for many years. More that 50% of people who undergo dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more for more than 10 years develop cysts.

Acquired cysts usually cause no symptoms, but occasionally people have blood in the urine Blood in Urine Blood in the urine (hematuria) can make urine appear pink, red, or brown, depending on the amount of blood, how long it has been in the urine, and how acidic the urine is. An amount of blood... read more (hematuria), pain in the side Flank Pain Pain caused by kidney disorders usually is felt in the side (flank) or small of the back. Occasionally, the pain extends to the center of the abdomen. Usually pain occurs because the kidney’s... read more (flank), or infection (typically causing fever and pain in the side). People with acquired cysts, particularly people with a transplanted kidney Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more or who have been treated with dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more
for several years, are at risk of kidney cancer Kidney Cancer Most solid kidney tumors are cancerous, but purely fluid-filled tumors (cysts) generally are not. Almost all kidney cancer is renal cell carcinoma. Another kind of kidney cancer, Wilms tumor... read more . For this reason, some doctors use ultrasonography Ultrasonography There are a variety of tests that can be used in the evaluation of a suspected kidney or urinary tract disorder. (See also Overview of the Urinary Tract.) X-rays are usually not helpful in evaluating... read more or computed tomography Computed tomography There are a variety of tests that can be used in the evaluation of a suspected kidney or urinary tract disorder. (See also Overview of the Urinary Tract.) X-rays are usually not helpful in evaluating... read more (CT) to periodically monitor people with acquired cysts.
Acquired cysts are most often detected when CT or ultrasonography is done for some other reason.
Cysts that cause persistent bleeding or infection may require drainage or, rarely, surgery to remove part of the kidney or even the entire kidney (partial or complete nephrectomy). Cysts that develop into kidney cancers Cancers of the Kidney and Genitourinary Tract may also require nephrectomy, but this happens only rarely.
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
American Kidney Fund (AKF): Information about kidney disease, kidney transplant, and needs-based financial assistance to help manage medical expenses
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): General information on kidney diseases, including research discoveries, statistics, and community health and outreach programs
National Kidney Foundation (NKF): Information on everything from the basics of kidney function to access to treatment and support for people with kidney disease