Cysts in the lungs are called pulmonary cysts. Instead of fluid, they usually contain gas. They can affect breathing. They often develop as a person ages but may also indicate an underlying medical condition.

Lung cysts have many potential causes and can cause severe complications without detection and treatment.

This article will discuss what pulmonary cysts are, why they occur, and the treatment options available. It will also look at when a person should seek medical help.

A healthcare professional examining an x-ray of the lungs to look for cysts.Share on Pinterest
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Healthcare professionals define a pulmonary cyst as a round space with a wall that usually has a thickness of up to 2–3 millimeters (mm).

Although these cysts occasionally contain fluid or solid material, they typically contain gas.

According to an older 2010 article in the American Journal of Roentgenology, there are several different types of lung cyst:

  • Blebs and bullae: These are small collections of gas that usually occur between the lung and the outer surface of the lung. Blebs are under 1 centimeter (cm) in diameter, and bullae are over 1 cm in diameter. Bullae can become substantial in size and can sometimes take up an entire lobe of the lung.
  • Honeycombing: This occurs when there are multiple cysts of different sizes and thicknesses in multiple layers. It results in a pattern resembling a honeycomb.
  • Pneumatocele: This term refers to bullae that form after trauma to the lung due to conditions such as pneumonia or inhaling certain gases.

The symptoms of lung cysts may vary depending on the cause of the cysts.

Some people may have no symptoms at all. If symptoms do develop, however, they may include:

  • difficulty breathing
  • pain while breathing
  • wheezing
  • shortness of breath
  • frequently developing pneumonia

Some research suggests that singular lung cysts can develop as a person ages.

However, they may also occur due to cystic lung disease. Cystic lung disease includes a group of conditions wherein multiple cysts have developed. Healthcare professionals may diagnose cystic lung disease if there are five or more cysts present.

Some causes of lung cysts include:

Birt-Hogg-Dubé syndrome

Birt-Hogg-Dubé (BHD) syndrome is a rare hereditary condition that develops due to mutations of certain genes.

Healthcare professionals initially thought that it was a skin condition. However, it can also cause lung cysts.

According to the BHD Foundation, 9 out of 10 people with BHD may experience blebs or bullae pulmonary cysts.


To treat the cysts, a healthcare professional may recommend a blebectomy or a bullectomy. These are surgical procedures to remove the cysts.


Lymphangioleiomyomatosis (LAM) is a rare condition that occurs almost only in females. It mostly affects the lungs, but it can also affect the kidneys and lymphatic system.

A genetic change affects abnormal cells called LAM cells, which causes them to grow throughout the lungs. This causes cysts, which can prevent oxygen from getting to the rest of the body.

Symptoms typically begin when a person is aged 20–40 years. They may include:

  • chest pain when inhaling
  • fatigue
  • collapsed lung, or pneumothorax
  • swollen lymph nodes
  • shortness of breath
  • wheezing
  • frequent cough


Treatment may involve:

  • mTOR inhibitors, to regulate the growth of LAM cells
  • bronchodilators, to help improve breathing
  • oxygen therapy

The only cure for LAM is a lung transplant.

Pulmonary Langerhans cell histiocytosis

Pulmonary Langerhans cell histiocytosis (PLCH) causes cysts to appear in the lungs. The cysts typically measure up to 10 mm in diameter. However, they can become as large as 20 mm.

PLCH occurs overwhelmingly in those who smoke, with 90–100% of people with PLCH falling into this category.

Symptoms may include:

  • breathlessness
  • fever
  • night sweats
  • weight loss
  • dry coughing


A person with PLCH should try to quit smoking. This can result in complete remission.

Other than quitting smoking, research suggests that there is no effective treatment.

Lymphocytic interstitial pneumonia

Lymphocytic interstitial pneumonia (LIP) is a group of symptoms that includes the development of lung cysts and:

  • shortness of breath
  • weight loss
  • fever
  • cough

Some research suggests that the cysts appear in approximately 80% of cases. Typically, only a few cysts appear, and they develop in both lungs.

They tend to measure up to 3 cm in diameter and vary in shape.

There is an association with underlying conditions such as HIV, Sjögren’s disease, Hashimoto’s thyroiditis, and systemic lupus erythematosus.


Treatment varies depending on the underlying cause of the LIP.

Other causes

Other conditions that may cause lung cysts include:

  • centrilobular and paraseptal emphysema, which are forms of chronic obstructive pulmonary disease
  • amyloidosis, which is a group of conditions that occur when a protein called amyloid builds up in the organs
  • pneumonia
  • some types of cancer, including:
    • metastatic cancer
    • squamous carcinoma
    • adenocarcinoma

A healthcare professional may ask about a person’s medical history and perform the following tests to diagnose the underlying condition causing lung cysts:

  • physical examinations
  • blood tests
  • imaging tests, such as CT scans

A solitary lung cyst may not be a cause for concern. This is because it may be the result of a person aging.

However, frequent or persistent cysts may indicate an underlying condition, and the outlook will vary depending on which condition a person has.

Lung cysts can cause pneumothorax, or collapsed lung.

This can happen when air gets into the space around a person’s lungs, such as if a lung cyst ruptures and the gas escapes into the pleural space.

If a person has a family history of lung cysts or any condition that may be known to cause lung cysts, they should speak with a doctor about their screening options.

Screening may involve having regular chest scans to keep an eye out for lung cysts so the doctor can start to monitor them before they cause a collapsed lung.

Smoking has associations with a variety of lung conditions, including lung cysts.

As a result, those who smoke may have a higher chance of developing cysts in their lungs.

If possible, those who smoke should consider quitting.

Learn about how to give up smoking here.

Lung cysts may be a part of aging. However, they may indicate some serious underlying conditions.

Detection usually only occurs when a person is having a scan for other reasons. However, if a person is experiencing breathlessness or other symptoms that may be cause for concern, they should seek medical advice.