Kidney Cyst

Medically Reviewed by Minesh Khatri, MD on August 14, 2022
4 min read

There are different kinds of kidney cysts. A simple kidney cyst is a round pouch of smooth, thin-walled tissue or a closed pocket that is usually filled with fluid. One or more may form within the kidneys. Simple cysts are the most common type of kidney cyst, and they most often are benign. 

Simple kidney cysts aren’t related to polycystic kidney disease (PKD). PKD runs in families and causes large numbers of cysts to grow in your kidneys. This makes your kidneys get larger and damages their tissue. 

Over time with PKD, your kidneys don’t work as well, and the disease can lead to kidney failure. Sometimes PKD can cause cysts to form in your liver or in other parts of your body. 

Acquired cystic kidney disease (ACKD) is another condition that causes cysts to grow in your kidneys. It doesn’t run in families like PKD, but happens in adults and children with chronic kidney failure and end-stage renal disease. ACKD doesn’t cause your kidneys to grow larger or lead to cysts in other parts of the body. It usually doesn’t cause symptoms or need treatment.  

Simple kidney cysts usually don’t cause symptoms. In most cases, a doctor finds them during an ultrasound or computerized tomography (CT) scan done for another reason. If you do have symptoms, they may include:

  • Pain in your side, back, or upper abdomen if they enlarge and press on other organs
  • Fever, chills, or other signs of infection
  • Blood in your urine
  • Blocked blood or urine flow through your kidneys (rare)
  • Impaired kidney function (rare)

Simple kidney cysts have been associated with high blood pressure, but it is unclear what the relationship is between the two.

PKD can cause symptoms including:

  • High blood pressure
  • Back or side pain
  • Blood in your urine
  • Headaches
  • Urinary tract infections
  • Kidney stones

Doctors don’t fully understand the cause of simple kidney cysts, but they don’t appear to be inherited. Men are more likely to get them than women. And almost half of all people aged 50 or older have one or more simple cysts in their kidneys. The size of these cysts may also increase with age and may double over 10 years.

PKD is caused by abnormal changes in genes, called mutations.

Doctors aren’t sure what causes ACKD.

Along with a physical exam and a family medical history, your doctor may use several tests to help them diagnose kidney cysts. These include:

  • Imaging tests, such as ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) scans
  • Blood tests to measure how well your kidneys work

If your cyst doesn’t cause symptoms or complications, you don’t need treatment. For a simple acquired cystic kidney you probably won’t need treatment.. However, in the rare case that you have symptoms, you may need treatment.

You may have a procedure called cyst sclerotherapy that involves these steps:

  • A doctor punctures the cyst with a long needle inserted through the skin, using ultrasound for guidance.
  • The doctor drains (aspirates) the cyst and may then fill the empty pouch with a solution that contains alcohol; this causes the tissue to harden and lowers the chances the cyst will come back. Scarring down the space within the cyst is called sclerosis.

In some cases, a cyst will return and refill with fluid. Your doctor may recommend surgery in which they give you drugs to make you sleep and make a large incision. During the procedure, the surgeon will insert a thin, lighted viewing tube called a laparoscope and other instruments to drain the fluid from the cyst and remove or burn its outer wall to keep it from returning.

You may need to stay in the hospital for one or two days following the surgery.

If your cyst doesn’t cause symptoms or complications, you don’t need treatment. For a simple acquired cystic kidney you probably won’t need treatment.. However, in the rare case that you have symptoms, you may need treatment.

You may have a procedure called cyst sclerotherapy that involves these steps:

  • A doctor punctures the cyst with a long needle inserted through the skin, using ultrasound for guidance.
  • The doctor drains (aspirates) the cyst and may then fill the empty pouch with a solution that contains alcohol; this causes the tissue to harden and lowers the chances the cyst will come back. Scarring down the space within the cyst is called sclerosis.

In some cases, a cyst will return and refill with fluid. Your doctor may recommend surgery in which they give you drugs to make you sleep and make a large incision. During the procedure, the surgeon will insert a thin, lighted viewing tube called a laparoscope and other instruments to drain the fluid from the cyst and remove or burn its outer wall to keep it from returning.

You may need to stay in the hospital for one or two days following the surgery.