
Cysts can appear on your kidneys, especially as you get older. Almost half of people aged 50 years or older have kidney cysts. They’re more likely to occur in men than women, and they sometimes don’t present any symptoms.
What are kidney cysts?
The kidneys are two bean-shaped organs located in your upper abdomen. They filter all the waste from your blood and expel it through your urine.
Cysts, or small sacs filled with watery fluid, can appear on the exterior of the kidneys and often don’t cause symptoms. They can grow as small as a pea or as big as a golf ball, and are circular or ovular in shape. These are called simple kidney cysts, which don’t usually affect the function of the kidney.
Main symptoms
Often, simple kidney cysts have no symptoms. The doctor may discover it while performing an imaging test for another reason.
You’ll likely start to experience these symptoms if the cyst grows, bursts, or becomes infected:
- Pain or discomfort in the upper abdominal area
- Blood in your urine or problems passing urine
- High blood pressure
- Fever
If you have any of these symptoms, you should seek medical attention. Cysts may cause a slight decline in kidney function.
Main causes
It’s not known why simple cysts appear on the kidney, but it’s more likely to happen as you age. Since doctors don’t know what causes them, they’re difficult to prevent.
Some diseases can cause kidney cysts, including polycystic kidney disease (PKD). People who have PKD develop groups of cysts inside their kidneys. PKD runs in families and can cause the kidney to stop functioning properly.
People with chronic kidney disease may develop acquired cystic kidney disease (ACKD). This is even more likely if they are on dialysis. Here, cysts appear only on the kidneys, which are normal in size, and not in other areas of the body. ACKD does not usually have symptoms.
Who can get them
Simple kidney cysts are more likely to happen as you get older, and men are twice as likely to develop them than women. People who smoke or have high blood pressure also have a greater chance of developing kidney cysts. Those with a genetic predisposition or who have a medical condition, such as polycystic kidney disease, are more susceptible as well.
Diagnosis for kidney cysts
An imaging test diagnoses kidney cysts. If you suspect that you have a cyst on your kidney or are experiencing symptoms, the doctor will take a look at your medical history and recommend one of the following tests for you:
- Magnetic resonance imaging (MRI)
- Ultrasound
- Computed tomography scan (CT scan)
A technician will perform the imaging test and collect the images. Once they’ve gone over them, they’ll be able to tell your doctor what type of cyst you have: simple or complex. Simple cysts don’t usually require as much medical attention as complex ones. Complex cysts can be linked to cancer.

Treatments for kidney cysts
If you don’t feel any pain from your simple kidney cyst, the doctor may not do anything right away. They may want to monitor it by taking more imaging tests at a later date.
Medications
If your cyst becomes infected, the doctor may recommend a course of antibiotics to treat the infection.
Alternative therapies
If you have symptoms, your doctor may need to perform a procedure called sclerotherapy, which happens under local anesthesia. For this treatment, the doctor inserts a needle through the skin into the cyst, removing the liquid. They then inject an alcohol solution to harden the area and ensure that the cyst doesn’t fill up again.
Surgery
Laparoscopic surgery (surgery using narrow tubes inserted in the abdomen through small incisions) is sometimes necessary if the cyst is large. The surgeon drains the cyst and removes the extra tissue around it. This procedure usually occurs under general anesthesia and may require you to remain in the hospital for one or two days.
Possible complications and side effects
It’s rare for a simple kidney cyst to cause complications, but it can happen. Simple kidney cysts can:
- Become infected, causing pain, tenderness, or fever
- Burst and cause blood in the urine
- Cause high blood pressure.
- Press on other organs or bones, leading to discomfort or pain
- Block the flow of urine or blood through the kidneys
If you’re aware of a cyst on your kidney, you should seek medical treatment immediately if you experience:
- sudden fever
- pain in the upper abdomen
- blood in your urine
- problems passing urine

SLIDESHOW
Kidney Stones: Symptoms, Causes, and Treatment See SlideshowHealth Solutions From Our Sponsors
Cedars Sinai: "Simple Kidney Cysts."
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