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. Overview of 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. Irritation of the lung lining, or pleura, can lead to inflammation and plaque development.

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.

People may be exposed to asbestos at work, at home or in their natural surroundings. Exposure at work seems to cause more plaques than asbestos in the environment.

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 who held any of the listed jobs are at risk of developing asbestos conditions, including plaques. If a worker has pleural plaques, they may not have symptoms. This means plaques can go undiagnosed until a more serious asbestos illness arises.

Individuals with a history of asbestos exposure should discuss it with their doctors. Physicians can help monitor for signs of asbestos cancers and illnesses.

03. How Pleural Plaques Develop

How Does Asbestos Cause Pleural Plaques?

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

In some cases, plaques may develop in the inner layer, or the visceral pleura. Plaques can also develop on 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.

This scarring process triggers the formation of pleural plaques over time. The plaques look like contained areas of thick, scar-like tissue on the lung lining.

Pleural plaques may have a rubbery quality early on. But they can harden through a process called calcification. This may make the plaques tougher and thicker.

What Are Calcified Pleural Plaques?

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.

It can take many years for pleural plaques to develop after asbestos exposure. This period of time between exposure and plaque appearance is the latency period. Research indicates pleural plaques often have a latency period of 20 years or more.

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. The researchers analyzed instances of pleural plaques, pleural thickening and the prevalence of future mesothelioma diagnoses. Workers with pleural plaques were more likely to develop mesothelioma than those without plaques.

This data does not mean pleural plaques directly lead to cancer. But they may indicate a higher risk of developing 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 coincidentally diagnosed when patients undergo these tests for other reasons.

The plaques appear 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 may 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.

Imaging scans that may detect pleural plaques include CT scans and X-rays.

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

Diagnosing Plaques With CT Scan

Experts generally agree CT scans are the best way to diagnose pleural plaques. In one study, CT scans identified existing pleural plaques in 95% of patients with the condition.

Finding Pleural Plaques on X-Ray

Some cases of pleural plaques may appear on a regular chest X-ray, but many do not. According to experts, X-rays are not a dependable way to detect pleural plaques. But a chest X-ray may appear abnormal in a person with plaques. This can trigger further imaging with a CT scan, which can diagnose pleural plaques.

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. And patients tended to have other conditions that could have caused their symptoms. So it remains possible that pleural plaques generally do not cause symptoms.

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

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.” This term means that the plaques look like small areas of thicker tissue on the lung lining. Its label can confuse people, as it sounds very similar to a different asbestos illness called diffuse pleural thickening. This condition happens when the entire lung lining thickens with scar tissue. Publications often refer to this condition as simply “pleural thickening.”

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.

05. Are Pleural Plaques Dangerous?

How Serious Are Pleural Plaques?

Pleural plaques are generally considered a benign condition with most cases being asymptomatic. The condition does not usually impact patients’ quality of life, and treatment is typically not required for pleural plaques.

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.

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 physicians. 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.

06. Common Questions

Common Questions About Pleural Plaques

Can pleural plaques turn into cancer?

Pleural plaques are not known to turn into cancer. But they may suggest a person has been exposed to asbestos. Pleural plaques may mean a person has an increased risk of developing mesothelioma. People with a history of asbestos exposure should discuss it with their doctors. Physicians can help monitor for signs of asbestos cancers and illnesses.

Are pleural plaques the same as mesothelioma?

Pleural plaques and mesothelioma are not the same condition. Mesothelioma is a rare, aggressive cancer that requires treatment. Pleural plaques are benign (not cancerous) and do not cause symptoms or need treatment. Patients with pleural plaques may have a higher risk of mesothelioma.

Can you get compensation for pleural plaques?

Possibly. People interested in compensation for pleural plaques should speak to an experienced asbestos attorney to understand their options.