Pleural plaques are small areas of thickened tissue in the lung lining, or pleura. They typically develop 20 – 30 years after prolonged asbestos exposure. Pleural plaques are usually benign and do not require treatment. Patients with pleural plaques can live for many years without any serious health problems.

01. What Are Pleural Plaques?

What Are Pleural Plaques?

Pleural plaques are the most common sign of asbestos exposure. They are grey-white areas of thickened tissue in the lung lining (pleura). Pleural plaques are sometimes referred to as hyaline pleural plaques. This is because they are composed of cartilage-like tissue (hyaline collagen).

In one study, researchers found about 89% of people exposed to asbestos later developed pleural plaques.

Unlike other serious asbestos-related diseases such as malignant mesothelioma, pleural plaques are non-cancerous.

Pleural plaques rarely present with symptoms and require little to no medical intervention. However, some research has indicated patients diagnosed with pleural plaques have a higher chance of developing pleural mesothelioma or other asbestos-related diseases.

02. Causes of Pleural Plaques

What Causes Pleural Plaques?

Pleural plaques are most commonly caused by asbestos exposure. After an individual inhales asbestos, the fibers can embed in the lung lining and cause irritation.

Researchers believe the lymphatic system carries the asbestos fibers to the pleura. The lymphatic system helps rid the body of waste and toxins. However, asbestos fibers are very small and may become stuck in the lining of organs.

Who Is at Risk for Developing Pleural Plaques?

Pleural plaques are common among workers exposed to asbestos on the job. This is likely due to prolonged asbestos exposure. However, some research indicates low levels of exposure can still cause pleural plaques.

Occupational asbestos exposure is very common among some professions, including:

People exposed to asbestos are at risk of developing pleural plaques. Pleural plaques are the most common asbestos-related disease.

03. How Pleural Plaques Develop

How Do Pleural Plaques Develop?

Pleural plaques may begin to develop once asbestos fibers reach the pleura. They often develop in the outer membrane of the lung lining that attaches to the chest wall. This membrane is called the parietal pleura.

In some cases, plaques may develop in the inner membrane, or the visceral pleura. Plaques can also develop in the diaphragm after ingestion or inhalation of asbestos fibers.

The asbestos fibers cause inflammation and fibrosis over time. Fibrosis is the overgrowth, hardening and/or scarring of tissue.

Pleural plaques present as localized fibrous deposits that thicken the lining of the lung. They develop as white lesions with a rubbery consistency, though may become calcified over more time.

What Is Calcification?

Calcification is the buildup of calcium salts in tissue. Calcium salts are similar to the substance that forms and hardens bone. Pleural plaques become calcified when calcium salts build up and harden.

Researchers have observed an average latency period of 20 years before pleural plaques may develop. Some patients have experienced the condition much sooner.

How Are Pleural Plaques Related to Mesothelioma?

Pleural plaques may be a risk factor for developing mesothelioma later.

In one study, researchers observed more than 13,000 asbestos workers from 2003 to 2011. The researchers analyzed instances of pleural plaques, pleural thickening and the prevalence of future mesothelioma diagnoses.

They found pleural plaques may be an independent risk factor for pleural mesothelioma.

Asbestosis and Pleural Plaques

Pleural plaques and asbestosis are unique conditions caused by asbestos exposure. Asbestosis is a non-cancerous condition with scarring and inflammation of the lungs. Some studies have found co-occurrence between the two conditions. Other studies indicate plaques may be a precursor to asbestosis.

04. Diagnosing Pleural Plaques

How Are Pleural Plaques Diagnosed?

Pleural plaques are typically identified through imaging scans. The condition is benign and often asymptomatic. As a result, many cases are accidentally diagnosed when patients undergo these tests for other reasons.

Imaging scans that may detect pleural plaques include:

  • A Chest X-Ray may be able to detect pleural plaques, especially if they are hardened and have defined edges.
  • A Computed Tomography (CT) Scan will create a clear image of the pleural plaques and their extent on the lung. Doctors generally prefer a high-resolution chest CT scan as it is more sensitive and specific than a chest x-ray. It can detect asbestos lung diseases even in early stages.

The condition appears as thickened areas of the lung with well-defined edges. Researchers call this “a holly leaf” shape. The impacted areas of the lung may be more visible if the patient has calcified pleural plaques.

On the scan, health care professionals will be able to see well-defined areas of thickening. These areas are often described as nodular, linear structures on the surface of the lung tissue. Some researchers have even noted they resemble a basket weave.

Detecting pleural plaques can be difficult because the condition rarely causes many symptoms.

What Are the Symptoms of Pleural Plaques?

In very rare cases, some patients have experienced chest pain, a cough or slight difficulty breathing at times. Pleural plaques do not generally cause pain or breathlessness. As a result, researchers believe these symptoms may be caused by co-occurring conditions, and not the plaques themselves.

Overall, doctors have noted pleural plaques do not have much influence on lung function or cause many health problems.

Because pleural plaques are usually linked to asbestos exposure, individuals aware of past exposure may choose to have regular screenings for any signs of asbestos disease.

Differentiating Pleural Plaques From Other Asbestos Diseases

Plaques may co-occur with conditions that do have symptoms, such as pleural thickening, asbestosis and mesothelioma.

Some studies refer to pleural plaques as “localized pleural thickening.” However, pleural thickening is its own distinct condition, though it may co-occur with pleural plaques.

While pleural plaques are benign, pleural thickening can cause more severe health issues. Pleural thickening may even be a sign of a more dangerous diagnosis such as mesothelioma.

It is important for doctors to take care in properly differentiating these diagnoses.

05. How Serious Are Pleural Plaques?

How Serious Are Pleural Plaques?

Pleural plaques are generally considered a benign condition with most cases being asymptomatic. As a result, the condition often does not impact patients’ quality of life.

Can Pleural Plaques Be Treated?

It is uncommon for patients to require any treatment for a pleural plaque diagnosis. This is because the areas of thickening often stay localized and don’t cause symptoms. Doctors may recommend lifestyle changes to help the lungs stay strong.

Are Pleural Plaques Life-Threatening?

Pleural plaques alone are not life-threatening. However, researchers have found patients with this condition may have a higher risk of pleural mesothelioma. Mesothelioma is serious and should be addressed as soon as possible.

The condition doesn’t generally require treatment on its own. However, doctors may recommend pulmonary function tests or lung function tests. These tests will observe lung capacity and how oxygen reaches the bloodstream.

Doctors may also recommend patients follow a healthier lifestyle to keep lung function strong. Doctors’ recommendations for a healthier lifestyle may include:

Though smoking does not directly cause asbestos diseases, quitting will help with overall lung health.

Pleural plaques may put patients at an increased risk of pleural mesothelioma. Patients aware of past asbestos exposure should talk to their physician. A doctor may recommend methods to monitor for signs and symptoms of mesothelioma. Lung function tests and an open dialogue with your doctor may help ensure the aggressive cancer is detected early if it should develop.