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Pleura are thin membranes that surround the lungs and line the chest cavity. When cancer begins in this tissue, it is most likely due to pleural mesothelioma. In addition to pleural mesothelioma, there are other problems that can originate in the pleura that may or may not be related to cancer. Pleural plaques are areas of thickened tissue in the pleura. Most often caused by asbestos, Pleural plaques pare the most common sign of asbestos damage to the chest cavity.
Plaques may not develop until many decades after asbestos exposure. They do not typically cause symptoms and may or may not develop into malignant pleural mesothelioma. By themselves, plaques are benign and do not cause health problems. Pleural plaques do not always worsen over time. Usually treatment is unnecessary. However, monitoring them for progression or cancer is important.
A Common Result of Asbestos Exposure
Asbestos, the natural material once used extensively in construction, shipbuilding, and other industries, has caused untold damage for those exposed to it. If you worked around asbestos during your career, you may have inhaled loose fibers of this material. Once inhaled, these tiny microscopic fibers easily become lodged in the body’s tissues. Most often, they lodge in the pleura of the chest cavity.
Once lodged, these fibers may cause damage over time. Not everyone exposed to asbestos will experience tissue damage. However, among those who do, pleural plaques are quite common. A plaque occurs when asbestos fibers cause tissue to become fibrous and hard. Exactly why this happens is not fully understood but is likely related to inflammation and scar tissue caused by asbestos fibers.
Pleural plaques are the most common complications of asbestos exposure. Their formation can be triggered by low levels of exposure as compared to conditions like asbestosis and mesothelioma. Research also suggests that plaque development is slow and may not be visible on imaging scans until many years after an initial exposure to asbestos.
How Pleural Plaques Form
Researchers do not understand exactly how these plaques form. They may be caused by inflammation and scar tissue, but there may be other pathways to their development. For example, some experts hypothesize that asbestos fibers trigger an immune system response. This may cause a type of immune cell called a macrophage to visit the site of damage, causing a reaction that leads to fibrosis and hardening of the tissue. Scar tissue that forms is made of collagen.
Pleural Plaques versus Pleural Thickening
Pleural thickening is another common result of asbestos damage to the pleura. This condition is easily confused with pleural plaques. Plaques are small, spaced apart, asymptomatic, and typically benign. Thickening tends to be more widespread. It likely affects the entire pleural surface and worsens over time. Symptoms also typically accompany pleural thickening and get worse as the condition progresses.
Symptoms of Pleural Plaques
Most people with pleural plaques only experience mild symptoms if they have symptoms at all. Some research has found that people with plaques have a slightly diminished lung capacity and function. Rarely a person with pleural plaques experiences chest pains and difficulty breathing.
Diagnosing Pleural Plaques and Mesothelioma
Most people diagnosed with pleural plaques had no symptoms leading up to diagnosis. Often, diagnosis is made after a patient has a chest X-ray done for other reasons. Plaques may appear on the X-ray image even though they are not causing symptoms. If plaques are discovered on your X-ray, talk to your doctor about your risk for mesothelioma. Further tests can see if you have early signs of cancer.
Imaging scans like CT scans, may show a pleural plaque as a mass on the lungs or pleura. This mass is often confused with cancer, making imaging tests ineffective for proper diagnosis. A biopsy is necessary when it is unclear if an abnormality or is a plaque or a cancerous growth. A small sample of the abnormal tissue is taken, usually through the insertion of a long needle, then examined under a microscope. A pathologist will look at the cells in the sample to determine if they are malignant or benign.
For most people diagnosed with pleural plaques, no treatment is necessary. The plaques are unlikely to cause symptoms or progress. However, if doctors discover you have plaques, it is important to reduce risk factors for related diseases like mesothelioma. If you still work with asbestos, take steps to eliminate that exposure. If you are a smoker, it is time to quit. Ask your doctor for advice on other measures you can take to minimize your risks. If you have symptoms, your doctor can prescribe medications or therapies that may help.
The prognosis for pleural plaques is generally positive. There is no evidence that plaques will develop into mesothelioma or lung cancer. However, plaques are a risk factor for these types of cancer, because they indicate you were likely exposed to asbestos. Any exposure to asbestos puts you at risk for later developing mesothelioma. Monitor your symptoms, reduce risk factors, and see your doctor for regular screenings.
Pleural plaques are not usually serious health problems and are unlikely to cause debilitating symptoms. However, plaques should be considered a wake-up call. They could be a sign that asbestos may have been in your workplace, causing exposure, and increasing your risk of mesothelioma. If you get sick with other related conditions, find out how a mesothelioma lawyer or asbestos trust fund could help you get compensation.
Page Medically Reviewed and Edited by Anne Courtney, AOCNP, DNP
Anne Courtney has a Doctor of Nursing Practice degree and is an Advanced Oncology Certified Nurse Practitioner. She has years of oncology experience working with patients with malignant mesothelioma, as well as other types of cancer. Dr. Courtney currently works at University of Texas LIVESTRONG Cancer Institutes.