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Simple kidney cysts: what they are, the symptoms, the tests, and when they need treatment
For anyone who was told a scan found a cyst on their kidney; anyone waiting to hear what a kidney cyst means; anyone with a kidney cyst who now has pain, fever or blood in their urine; and anyone looking after someone who does. It passes on, by name, what the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, part of the NIH) says: what simple kidney cysts are, how common they are and who gets them; the rare problems they can cause; the imaging and lab tests; watching them, draining them, and surgery; and how they differ from polycystic kidney disease (PKD). It builds the words to say to your care team, so you do not have to find them, and prints a card.
Right now
- Pain, fever, or blood in your urine, with a kidney cyst? NIDDK says to talk with your health care professional. Ours: if you believe it is an emergency, call 911; you do not need to be sure. See kidney infection and blood in the urine.
- Is it all too much, or is someone thinking of ending their life? Call or text 988, any hour (ours).
More help
- On this site: Kidneys, bladder and urine: find the right page · When it’s your kidneys · Polycystic kidney disease (PKD) · A solitary kidney.
- Related: Kidney infection · Blood in the urine · High blood pressure · Kidney stones.
- Getting ready: Symptom diary · Get ready for your appointment · When you need a doctor and can’t pay.
- In a crisis: Help right now (988, 911). All our free tools.
Kidneys, bladder or urine, and not sure this is the right page? The pages on this site for bladder infections, kidney stones, blood in the urine, bladder pain, bladder leaks, the prostate, kidney disease and bedwetting, on one list.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 19, 2026 on NIDDK’s (NIH) page Simple Kidney Cysts (last reviewed June 2019) and its Spanish page Quistes renales simples (last reviewed June 2019), which say the same. The numbers (in one large study about 1 in 10 people had simple kidney cysts, nearly 1 in 5 of people age 50 and older; in one study men were twice as likely; 1 or 2 days in the hospital after surgery) are NIDDK’s, from the studies it cites. Ours: “if you believe it is an emergency, call 911” (NIDDK names no 911 on this page); 988; the questions to ask; the links to our other pages; and the order of the steps. What we left out: the section on clinical trials, the journal articles NIDDK cites, and NIDDK’s links to other sites. Nothing you tick or type here is saved or sent.