11 Min Read
Last Updated: 05/23/2024
Fact Checked

Written by Karen Selby, RN | Medically Reviewed By Dr. Wickii Thambiah Vigneswaran | Edited By Walter Pacheco

What Is Pleural Thickening?

Pleural thickening is irritated and inflamed tissue in the lining of the lungs or pleural membrane. This thickening is the result of scarring (fibrosis) on the pleural membrane from long-term (chronic) inflammation. Specifically, pleural parenchymal scarring is a form of scar tissue buildup that occurs with pleural thickening.

pleural thickening's effect on the lungs

Asbestos is not the only cause of pleural thickening. However, it is considered an asbestos-related disease because it can be a sign of asbestos exposure. 

Pleural plaques are different from pleural thickening. These plaques are made of hyaline tissues found in cartilage. Pleural plaques are also smaller than pleural thickening. 

Types of Pleural Thickening

Pleural thickening can be divided into two main categories: Focal and diffuse. Within these groups, specific cases can either be benign or malignant.

Different Kinds of Pleural Thickening
  • Benign Pleural Thickening: Non-cancerous thickening of the pleura. The buildup of fibrous tissue is the main cause.
  • Diffuse Pleural Thickening: Large or widespread thickening that is seen on imaging scans taking up 50% or more of the left or right pleura or 25% of both pleurae.
  • Focal Pleural Thickening: Thickening in one specific area of the pleura.
  • Malignant Pleural Thickening: Cancerous thickening of the pleura from malignant pleural mesothelioma or metastatic cancer from another site in the body.

Pleural thickening can develop in different parts of the lung, on one side or both. Your doctor may use specific terms when referring to your case. 

Thickening in the top portion of the lung is called apical pleural thickening. The term for thickening that affects either the left or right lung is unilateral pleural thickening. Bilateral affects both lungs. Some people have nodular pleural thickening, which forms rounded bumps or nodules. 

Key Facts About Pleural Thickening
  • Asbestos exposure is the primary cause of pleural thickening.
  • Difficulty breathing is the most common symptom of pleural thickening.
  • Doctors use X-rays, MRIs and CT scans as diagnostic tools.
  • Pleural thickening can be a sign of extensive asbestos exposure, which is a high risk factor for developing mesothelioma.

What Causes Pleural Thickening?

Asbestos exposure is one of the primary causes of pleural thickening. While asbestos exposure is the most common cause, other diseases that cause acute or severe inflammation of the pleura can also lead to pleural thickening.

Pleural Thickening Causes
  • Asbestos
  • Chest or rib injuries
  • Coronary artery bypass grafting (CABG) surgery
  • Empyema or accumulation of pus in the pleural space because of infection
  • Hemothorax or accumulation of blood in the pleura from chest injuries
  • Infections such as tuberculosis or chronic pneumonia
  • Lung tumors (benign or malignant)
  • Malignancies, including sarcoma and lymphoma
  • Pleural effusion or fluid buildup in the pleura
  • Pulmonary embolism or a blood clot in the lungs
  • Radiation exposure

Asbestos dust contains microscopic mineral fibers that become lodged in the pleura when inhaled. When these asbestos fibers are stuck in the lining of the lungs, they cause inflammation, leading to fibrous scar tissue buildup. This eventually can lead to pleural thickening.

It’s important to discuss your health history with your doctor so they’re aware of your risk of pleural thickening. If you have a known history of asbestos exposure, be sure to discuss this with your healthcare provider and ask about screenings for asbestos-related diseases such as mesothelioma.

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What Are Common Pleural Thickening Symptoms?

The most common symptoms of pleural thickening are breathlessness, chest pain and coughing. Some patients also experience fever. Scar tissue formation in pleural thickening prevents the lungs from expanding, which leads to these uncomfortable symptoms. 

“Pleural thickening causes shortness of breath and chest pain,” said Sean Marchese, a registered nurse and oncology writer at The Mesothelioma Center at Asbestos.com. “Over time, it can cause decreased levels of oxygen.”

A 2023 study of pleural thickening also noted that patients can experience “progressive decline in pulmonary function” and emphasized the experience of “pleuritic pain.” The authors explained that while other literature on the subject seemed to suggest that pleural thickening symptoms didn’t have a significant impact on “pulmonary function and physiology,” they found in the patients they studied that “PT plays a role in declining vital capacity in those with prolonged or unusual exposures” to asbestos.

Survivor Story
Jim McWhorter Pleural Mesothelioma

Pleural Thickening Was a Sign of Survivor’s Mesothelioma Journey to Come

Survivor Story

Jim McWhorter was told an injury-prompted x-ray was clear, but pleural thickening was noted in his record. A later decortication for suspected infection found tumors, but Jim was told not to worry. His wife told us, “We got the CT scan report saying ‘Nodular thickening. Suspect for mesothelioma. Doctors should take immediate action.’ If we’d known, we’d have sought a specialist.”

Read Jim’s Story

How Is Pleural Thickening Diagnosed?

film chest X-ray PA upright : show pleural effusion at right lung due to lung cancer.
Imaging scans can show signs of pleural effusion.

The most common way to diagnose pleural thickening is with imaging studies, such as X-rays, CT scans or MRIs. If you’re experiencing pleural thickening symptoms, talk to your doctor. They’ll likely run diagnostic tests.

These screening tests are also used to eliminate the possibility of other diagnoses, such as pleural plaques. They should not be confused with pleural thickening, but asbestos exposure causes both conditions. 

To help ensure an accurate diagnosis, it’s vital to share your history of possible asbestos exposure with your doctor. If you’re unsatisfied with your screening results, you can always get a second opinion on your diagnosis. 

One review of multiple studies found that pleural thickening occurs in 5% to 13.5% of asbestos-exposed workers. The condition may develop within one year of exposure, or it may arise several years later. 

X-ray Imaging Scans

Pleural thickening is usually spotted through a chest X-ray. In fact, it’s commonly found in routine chest X-rays along the edges of the lung. This is because the X-ray beam passes through the edges tangentially (not straight through), so it’s easier to visualize. 

About 50%

Percentage of pleural mesothelioma cases showing pleural thickening.

Source: Japanese Journal of Radiology, Volume 42

Fat along the pleura (extrapleural fat) may also look like pleural thickening, which may lead to a misdiagnosis. With this, X-ray images are not the most accurate. To confirm a pleural thickening diagnosis, other imaging techniques may be used.

CT Scans

CT scans are the primary imaging method for diagnosing pleural thickening. This method measures pleural thickening less than 1 centimeter thick, which can help diagnose early cases. CT scans take multiple high-resolution images at several angles (planes), providing more detail than chest X-rays. 

Doctors also use CT scans to guide needle biopsies, allowing them to take tissue samples. Biopsies are a key part of accurately diagnosing lung diseases. 

CT scans are highly sensitive because they use a contrast agent injected into the veins. Contrast helps radiologists visualize the pleura. However, the contrast agent may not be used in patients with poor kidney function or those who are allergic. 

PET Scans and MRIs

Doctors can use PET scans and MRI scans to distinguish between pleural thickening and pleural mesothelioma. Pleural mesothelioma is cancer affecting the pleura and is often associated with asbestos exposure. 

PET scans use radiolabeled glucose molecules to look at tissues that are metabolically active. Tumors are generally active and they take up glucose molecules, which appear as bright spots on the PET scan. 

MRIs use a gadolinium contrast agent to help determine whether a patient has pleural thickening or pleural mesothelioma. If a patient can’t have the contrast agent used in CT scans, an MRI is a useful option for diagnosis.

Dr. Jacques Fontaine and Dr. Virginia Wolf
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Pleural Thickening Treatment

Pleural thickening has no cure and is usually limited to supportive treatment. The most beneficial options are typically to quit smoking, maintain an active lifestyle and undergo pulmonary rehabilitation. 

The effects of pleural thickening are irreversible in malignant pleural mesothelioma. However, steps may be taken to improve symptoms and quality of life. 

Surgery may be an option in some cases to improve breathing difficulty and other respiratory symptoms. Doctors perform surgical procedures to remove thickened pleural tissues or to treat underlying causes of pleural thickening. 

Pulmonary Rehabilitation

Pulmonary rehabilitation is a supervised exercise program developed for people with lung diseases. It focuses on helping patients regain strength and stamina through breathing techniques, exercises and nutritional counseling. Programs typically last several weeks to months. 

Pulmonary rehabilitation has been shown to help those with pleural thickening recover from their condition. One Australian study found that this program can significantly improve quality of life for patients with dust-related respiratory diseases, including pleural thickening. 

Smoking Cessation

For patients who smoke, quitting is essential after a diagnosis of pleural thickening. Smoking further reduces lung function. It also increases the risk of developing other respiratory diseases. As a result, this can aggravate pleural thickening and lead to worsening symptoms. One study found that pleural thickening is more common in current and ex-smokers compared to never smokers. 

Need help quitting? Your doctor can provide supportive care. Nicotine replacements or medications can help curb cravings. These treatments can improve your odds of successfully quitting for good. 

Doctors Who Treat Pleural Thickening

Pulmonologists and pleural specialists have the expertise to diagnose and treat pleural thickening. They can recommend follow-up care and watch your condition for signs of progression.

Dr. Wickii Thambiah Vigneswaran, pleural mesothelioma surgeon

Maywood, Illinois

Wickii Thambiah Vigneswaran

Pleural Specialist | Thoracic Surgery

Expertise: Thoracic Surgery Mesothelioma Lung and Lung/Heart Transplantations Pleurectomy and Decortication Robotic Surgery

Languages: English, Tamil

Dr. Jeffrey Velotta, thoracic surgeon

Oakland, California

Jeffrey Velotta

Pleural Specialist | Thoracic Surgery

Expertise: Pleural Mesothelioma, Lung Cancer, Cardiothoracic Surgery, Cardiac Surgery and Surgical Oncology

Languages: English

Dr. Raja Michael Flores, Chief of Thoracic Surgery

New York, New York

Raja Michael Flores

Pleural Specialist | Thoracic Surgery

Expertise: Pleural Mesothelioma, Pleurectomy and Decortication Surgery, Lung Cancer, VATS, Lobectomy, Thoracotomy and Clinical Research

Languages: English, Spanish

Dr. Jacques Fontaine, pleural mesothelioma doctor and expert contributor for Asbestos.com

Tampa, Florida

Jacques Fontaine

Pleural Specialist | Thoracic Surgery

Expertise: Pleural Mesothelioma, Lung Cancer, Thoracic Diseases, Minimally Invasive Surgery, Pleurectomy and Decortication Surgery

Languages: English, Spanish, French, Arabic

If you need assistance finding a pleural specialist, our Patient Advocates at The Mesothelioma Center can match you with a top doctor near you. Our team of Patient Advocates has been helping patients find doctors since 2006.

Is Pleural Thickening Serious? 

Pleural thickening isn’t always a serious health concern. However, if left untreated, pleural thickening can progress to advanced stages. Advanced pleural thickening can lead to the encasement of the lung and cause restrictive lung disease. This can significantly impact breathing and thus requires attention. 

Pleural thickening alone is not enough to confirm a pleural mesothelioma diagnosis. But it can be a sign of serious and significant asbestos exposure. It’s important to note that not every mesothelioma patient has pleural thickening. 

Catching mesothelioma at an early stage can offer more treatment options. Because an early diagnosis is critical, patients with asbestos-related pleural thickening should have regular cancer screenings.

Common Questions About Pleural Thickening

Does pleural thickening lead to mesothelioma?

Pleural thickening alone is not enough to confirm that you have asbestos cancer. However, it can be a sign of significant asbestos exposure and indicate a high risk for mesothelioma. Advanced pleural thickening can cause restrictive lung disease with severe breathing difficulty.

Can smoking cause pleural thickening?

Asbestos is the primary cause of pleural thickening. There are data that point to a correlation between smoking and the progression of pleural thickening. Smoking limits lung function and is proven to be a cause of other respiratory diseases, such as lung cancer.

Can pleural thickening affect your lifespan?

In most cases, pleural thickening will not affect lifespan. But this condition may be a sign of a more serious underlying condition such as malignant pleural mesothelioma or other cancer. Your doctor will determine how serious your pleural thickening is with diagnostic tests.

Have there been any asbestos lawsuits related to pleural thickening?

Yes, Miller v. Armstrong World Industries Inc. in 1991 was a precedent-setting court case. Raymond Miller was an insulator who used asbestos products and eventually developed pleural thickening. The Armstrong World Industries Asbestos Trust now accepts claims from individuals who experienced health effects from the company’s asbestos-containing products.

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