Kidney Cyst

A kidney cyst is a fluid-filled sac that forms on the surface of the kidney. Kidney cysts are usually noncancerous (benign) and can occur at any age.

Types of Kidney Cysts

  • Simple kidney cysts: These are the most common type of kidney cyst and are usually small and noncancerous. They can occur in one or both kidneys and may not cause any symptoms.
  • Complex kidney cysts: These cysts have a more complex appearance on imaging tests and may be more likely to be cancerous. However, most complex kidney cysts are still benign.
  • Polycystic kidney disease (PKD): This is a genetic disorder that causes numerous cysts to form in both kidneys. PKD can lead to high blood pressure, kidney damage, and eventually kidney failure.

Causes and Risk Factors

The exact cause of simple kidney cysts is not known, but they are thought to be related to the aging process. As people get older, the kidneys naturally lose some of their function, which can lead to the formation of cysts.

Risk factors for developing kidney cysts include:

  • Age: Kidney cysts are more common in people over the age of 50.
  • Family history: Having a family history of kidney cysts or PKD increases the risk of developing kidney cysts.
  • High blood pressure: High blood pressure can increase the risk of developing kidney cysts.

Symptoms

Many people with kidney cysts do not experience any symptoms. However, some people may experience:

Diagnosis

Kidney cysts are usually diagnosed with imaging tests, such as:

  • Ultrasound: This test uses sound waves to create images of the kidneys.
  • Computed tomography (CT) scan: This test uses X-rays and a computer to create detailed images of the kidneys.
  • Magnetic resonance imaging (MRI) scan: This test uses magnetic fields and radio waves to create detailed images of the kidneys.

Treatment

Treatment for kidney cysts depends on the size and location of the cyst, as well as the presence of any symptoms. In many cases, no treatment is needed, and the cyst can be monitored with regular imaging tests.

However, if the cyst is large or causing symptoms, treatment options may include:

  • Drainage: The cyst can be drained using a needle inserted through the skin.
  • Surgery: In some cases, surgery may be necessary to remove the cyst or part of the kidney.

Complications

Kidney cysts can increase the risk of certain complications, including:

  • Kidney damage: Large cysts can cause damage to the surrounding kidney tissue.
  • Kidney failure: In people with PKD, numerous cysts can lead to kidney failure over time.
  • Urinary tract infections: Kidney cysts can increase the risk of developing urinary tract infections.

Frequently Asked Questions (FAQs)

What is a kidney cyst?
A fluid-filled sac that forms on the kidney.

What causes kidney cysts?
Typically simple cysts are benign and may be due to aging or other factors, but the exact cause is often unclear.

Are kidney cysts usually cancerous?
Most kidney cysts are non-cancerous, but some can be associated with cancer.

Can kidney cysts cause symptoms?
Often they do not, but possible symptoms include pain, infection, or bleeding.

How are kidney cysts diagnosed?
Typically through imaging tests such as ultrasound, CT scan, or MRI.

Can kidney cysts be treated?
Treatment may involve monitoring, draining the cyst, or surgery, depending on size and symptoms.

Do kidney cysts affect kidney function?
Usually not, but large or numerous cysts can potentially impair kidney function.

Are kidney cysts inherited?
Some types of kidney cysts, such as those associated with polycystic kidney disease, have a genetic component.

Can kidney cysts increase the risk of kidney stones?
Possibly, as some studies suggest an association between kidney cysts and stone formation.

Should individuals with kidney cysts restrict their activities?
Generally, no specific restrictions are necessary unless advised by a healthcare provider due to related health issues.

Article last updated on: 18th October 2025.
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