Kidney cysts are round pouches of fluid that form on or in the kidneys. Kidney cysts can be associated with serious disorders that may impair kidney function. But more commonly, kidney cysts are a type called simple kidney cysts — noncancerous cysts that rarely cause complications.
It's not clear what causes simple kidney cysts. Typically, only one cyst occurs on the surface of a kidney, but multiple cysts can affect one or both kidneys. However, simple kidney cysts aren't the same as the cysts that form with polycystic kidney disease.
Simple kidney cysts are often detected during an imaging test performed for another condition. Simple kidney cysts that don't cause signs or symptoms usually don't require treatment.
A kidney cyst is a round or oval fluid-filled pouch with a well-defined outline. Kidney cysts typically grow on the surface of a kidney, although some may develop inside your kidney.
Simple kidney cysts typically don't cause signs or symptoms. If a simple kidney cyst grows large enough, symptoms may include:
Make an appointment with your doctor if you have signs or symptoms of a kidney cyst.
It's not clear what causes simple kidney cysts. One theory suggests that kidney cysts develop when the surface layer of the kidney weakens and forms a pouch (diverticulum). The pouch then fills with fluid, detaches and develops into a cyst.
The risk of having simple kidney cysts increases as you get older, though they can occur at any age. Simple kidney cysts are more common in men.
Kidney cysts can occasionally lead to complications, including:
Tests and procedures used to diagnose simple kidney cysts include:
If your simple kidney cyst causes no signs or symptoms and doesn't interfere with your kidney function, you may not need treatment. Instead, your doctor may recommend that you have an imaging test, such as ultrasound, periodically to see whether your kidney cyst has enlarged. If your kidney cyst changes and causes signs and symptoms, you may choose to have treatment at that time. Sometimes a simple kidney cyst goes away on its own.
If your simple kidney cyst is causing signs and symptoms, your doctor may recommend treatment. Options include:
Depending on the type of procedure your doctor recommends, treatment for your kidney cyst may require a brief hospital stay.
A simple kidney cyst discovered during an imaging test for another disease or condition may concern you. Talk with your doctor about what having a simple kidney cyst means for your health. Gathering information may put your mind at ease and help you feel more in control of your situation.
Before meeting with your doctor, prepare a list of questions to ask, such as:
Don't hesitate to ask other questions as they occur to you during your appointment.
Your doctor is likely to ask you a number of questions, such as: