Written By: Devin Golden

Pleural Thickening

Pleural thickening is scar tissue in the pleura that has formed due to asbestos exposure, or an infection. The pleura is the lining around the lungs and where pleural mesothelioma cancer forms. Pleural thickening is one of the symptoms of pleural mesothelioma cancer. It can cause a loss of elasticity in your lungs, which leads to difficulty breathing.

Karen Ritter, RN BSN

Medically Reviewed By

Karen Ritter, RN BSN

Registered Nurse


jump to icon


Important Facts About Pleural Thickening

  • Pleural thickening is often a symptom of pleural mesothelioma. It occurs when scar tissue builds up in the pleural, which is where pleural mesothelioma forms.
  • There are three types of pleural thickening: apical, focal and diffuse. Pleural thickening symptoms may resemble pleural mesothelioma symptoms: chest pain, pleural effusion, difficulty taking deep breaths and painful coughing.
  • Pleural thickening can be treated with pulmonary rehabilitation, which is a medical program designed to help people with lung diseases live and breathe better by using exercises and breathing techniques.

An Overview of Pleural Thickening

Pleural thickening occurs when scar tissue builds up in the pleura, which is the thin lining around the lungs. This lining is made up of two tissue layers and a space in between with pleural fluid. These two tissue layers are called the:

  • Parietal pleura – Outer layer attached to the chest wall
  • Visceral pleura – Inner layer attached to the lungs

Pleural thickening can either be malignant (cancerous) or benign (noncancerous).

Pleural Thickening Mobile
Pleural Thickening Desktop
Pleural Thickening Desktop

What is Pleural Thickening?

Types of Pleural Thickening Icon

Types of Pleural Thickening

Aside from being benign or cancerous, there are three types of pleural thickening:

  • Apical pleural thickening
  • Focal pleural thickening
  • Diffuse pleural thickening

Apical pleural thickening is scar tissue on the top-most portion of the pleural cavity. This type is most likely benign.

Focal pleural thickening is limited to just one part of the pleural cavity. Diffuse pleural thickening is more widespread throughout the pleura. Both focal pleural thickening and diffuse pleural thickening can be a sign of pleural mesothelioma. Diffuse pleural thickening has the greatest chance of impacting your breathing and causing chest pain.

Pleural Thickening Causes

There are a few pleural thickening causes. The main one is exposure to asbestos. Other causes of pleural thickening include: infections, such as tuberculosis or pneumonia; lung cancer; asbestosis (scarring of lung tissue); pulmonary embolism (blood clot in the lungs); and radiation.

Scar tissue can form in this cavity when sharp asbestos fibers penetrate the mesothelial cell linings within the pleural cavity and irritate tissue.

Pleural thickening usually does not develop immediately after someone is exposed to asbestos. The condition usually takes 20-50 years to develop after exposure. This is called the latency period.

If you were exposed to asbestos, then the likelihood of developing pleural mesothelioma is higher. Additionally, if your pleural thickening is a sign of pleural mesothelioma cancer, then you were exposed to asbestos at some point in your life.

Warning Icon

Risks of Developing Pleural Thickening

If you were exposed to asbestos, you have a higher risk of developing pleural thickening. Your occupation can increase your risk of asbestos exposure, which increases your risk of pleural thickening.

According to a study of 106 people with diffuse pleural thickening (widespread pleural thickening in the pleural cavity). The occupations with the highest incidence of pleural thickening were:

  • Asbestos product manufacturing (17)
  • Shipbuilding (14)
  • Construction (13)
  • Insulation work (12)
  • Plumbing (7)
  • Electrical work (7)
  • Transportation (4)
  • Demolition work (4)

All of these occupations can involve handling asbestos or working near loose asbestos fibers.

Other risks include getting infections, such as tuberculosis, or developing lung cancer.

Smoking Icon

Smoking is another risk factor for pleural thickening. According to a study in Respiratory Research, current or ex-smokers were more likely to develop pleural thickening than never-smokers. This could be due to the link between smoking and lung cancer, and how pleural thickening is a symptom of lung cancer.

Other risk factors for pleural thickening include gender (pleural thickening is more common in males) and age (pleural thickening is more common in seniors).

How to Diagnose Pleural Thickening

The most common ways to detect pleural thickening are through a chest X-ray or CT scan. According to the study in Respiratory Research, pleural thickening is the most common respiratory condition found in chest X-rays. Among nearly 28,000 people receiving a chest X-ray, pleural thickening was found in 3.2% of them.

CT scans are another primary image test to detect pleural thickening. CT scans show the entire pleura in detail, which reveals the extent and severity of pleural thickening. CT scans can also differentiate between pleural thickening and pleural plaques.

In a study of people with pleural mesothelioma cancer, around 88% showed pleural thickening on CT scans. These scans provide detailed two-dimensional images of the inside of the body. They’re commonly used in the process of diagnosing pleural mesothelioma.

Other tests to determine if you have pleural thickening include:

Ultrasound Image


MRI Scan Image

MRI scans

PET Scan Icon

PET scans

These image tests are better if your pleural thickening is believed to be a sign of pleural mesothelioma cancer. They can also differentiate between malignant pleural thickening and benign pleural thickening, which means they can help determine if you have cancer along with pleural thickening.

Pleural Thickening Symptoms

The symptoms of pleural thickening are in many ways similar to the most common pleural mesothelioma symptoms. Symptoms of pleural thickening include:

  • Chest pain
  • Difficulty exerting a lot of energy or exercising
  • Difficulty taking deep breaths
  • Shortness of breath
  • Painful coughing
  • Pleural effusion (buildup of fluid in the pleural cavity)

According to one study in Europe, more than half of patients with pleural thickening experienced chest pain.

Pleural Thickening and Pleural Mesothelioma

Pleural thickening can be a sign of asbestos exposure and a symptom of pleural mesothelioma. Pleural mesothelioma forms in the pleura and can cause pleural thickening scar tissue, which causes an inflammation of tissue.

In some cases of pleural mesothelioma, patients do not experience pleural thickening. So there isn’t a definitive link between pleural thickening and pleural mesothelioma. A report in ScienceDirect found pleural thickening in 88% of diagnosed pleural mesothelioma cases.

However, in cases of pleural mesothelioma with pleural thickening, it is specifically caused by scarring of the pleura due to asbestos fibers. 

Pleural Thickening and Other Conditions Icon

Pleural Thickening and Other Conditions

Pleural thickening can be a standalone health condition or a symptom of another condition. Therefore, pleural thickening does not always mean you were exposed to asbestos or that you have cancer.

Pleural thickening can also be a symptom of other diseases or infections, such as tuberculosis, pleurisy, hemothorax (buildup of blood in the pleural cavity), and empyema (infection in the lung that causes a buildup of pus in the pleura). Pleural thickening can also be a symptom of lung cancer.

Pleural Plaques and Pleural Thickening Icon

Pleural Plaques and Pleural Thickening

Pleural plaques are also the result of asbestos fibers causing scar tissue in the pleural cavity. The difference between pleural plaques and pleural thickening is the amount of scar tissue in the pleural cavity. Pleural plaques are defined by small, singular areas of scar tissue. Pleural thickening is defined by more widespread scar tissue in the pleural cavity.

Otherwise, pleural plaques and pleural thickening are similar. They can both be symptoms of pleural mesothelioma, and they both can be standalone health conditions defined by scar tissue caused by asbestos exposure.

Pleural Thickening Treatment

Many people with pleural thickening ask their doctors, “How is pleural thickening treated?” There are no curative treatment options for this condition. Pleural thickening is a scarring of tissue in the pleural cavity. It can impact respiratory function but otherwise is not a fatal condition.

Your life expectancy with pleural thickening is largely dependent on whether it’s a benign condition or a symptom of cancer, such as pleural mesothelioma. If your pleural thickening is benign, then your life expectancy is likely normal. If your pleural thickening is associated with a malignant condition, then your life expectancy will be lower than the average person.

One treatment method for pleural thickening is pulmonary rehabilitation.

Types of Pleural Thickening Icon

Types of Pleural Thickening

According to the National Heart, Lung, and Blood Institute, pulmonary rehabilitation is “a supervised medical program that helps people who have lung diseases live and breathe better.” The program includes exercises and breathing techniques.

Pulmonary rehabilitation can improve quality of life for patients and decrease discomfort caused by pleural thickening. Some of the elements of pulmonary rehabilitation include:

  • Exercise stress tests to measure oxygen levels, blood pressure and heart rate
  • Breathing tests to check lung function
  • Six-minute walk tests to measure physical capabilities
  • Breathing techniques to conserve breath and energy (lip breathing, yoga breathing, etc.)
  • Changes in lifestyle, such as quitting smoking and improving your diet

Frequently Asked Questions About Pleural Thickening

blue box icon

What Causes Pleural Thickening in the Lungs?

Asbestos fibers cause pleural thickening near the lungs. Asbestos fibers irritate tissue in the pleural cavity, which is a lining around the lungs. This irritation causes scar tissue, which is what leads to pleural thickening.

blue box icon

How Is Pleural Thickening Treated?

Pleural thickening is not treated as a standalone condition. It can lead to treatment if it causes severe symptoms or it’s a sign of a more serious condition, such as pleural mesothelioma.

blue box icon

How Are Pleural Plaques Treated?

Pleural plaques usually are not treated unless they are a symptom of a more serious condition. Pleural plaques on their own are benign (noncancerous). If pleural plaques are associated with pleural mesothelioma cancer, then doctors will treat the cancerous tumors.

blue box icon

Can Pleural Thickening Be Cured?

Pleural thickening cannot be cured. There are treatment options, such as palliative surgeries and pulmonary rehabilitation, to improve breathing and help the respiratory system function better. However, the buildup of scar tissue is irreversible.

blue box icon

Is Pleural Thickening Serious?

Pleural thickening can be serious, especially if it’s a sign of cancer, such as a symptom of pleural mesothelioma. Pleural thickening can also be a benign condition – meaning it’s not cancerous. People can live with pleural thickening if it’s not a symptom of a more serious condition. However, benign pleural thickening can impact respiratory function and cause breathing issues.

Sources & Author

  1. Pleural Mesothelioma. ScienceDirect. Retrieved from: https://www.sciencedirect.com/topics/medicine-and-dentistry/pleura-mesothelioma. Accessed: 07/15/2021.
  2. Pleural thickening on screening chest X-rays: a single institutional study. Respiratory Research. Retrieved from: https://respiratory-research.biomedcentral.com/articles/10.1186/s12931-019-1116-9. Accessed: 03/02/2023.
  3. Malignant Mesothelioma Versus Metastatic Carcinoma of the Pleura: A CT Challenge. Iranian Journal of Radiology. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4837229/. Accessed: 03/02/2023.
  4. Asbestos-Related Diffuse Pleural Thickening. Karger. Retrieved from: https://www.karger.com/Article/FullText/364948. Accessed: 03/02/2023.
  5. Asbestos-related bilateral diffuse pleural thickening: natural history of radiographic and lung function abnormalities. American Journal of Respiratory Care and Critical Medicine. Retrieved from: https://www.atsjournals.org/doi/abs/10.1164/ajrccm.153.1.8542134. Accessed: 03/02/2023.
  6. Pulmonary Rehabilitation. National Heart, Lung, and Blood Institute. Retrieved from: https://www.nhlbi.nih.gov/health/pulmonary-rehabilitation. Accessed: 03/02/2023.
Devin Golden

About the Writer, Devin Golden

Devin Golden is a content writer for Mesothelioma Guide. He produces mesothelioma-related content on various mediums, including the Mesothelioma Guide website and social media channels. Devin's objective is to translate complex information regarding mesothelioma into informative, easily absorbable content to help patients and their loved ones.