Pleural plaques are discrete, localized areas of thickened, often calcified tissue on the pleura — the lining of the lungs and chest wall. They are the most common sign of past asbestos exposure and serve as a reliable marker that a person inhaled asbestos fibers, usually decades earlier.
What Pleural Plaques Are
Plaques are patches of fibrous, sometimes calcified tissue that form on the parietal pleura (the layer lining the chest wall) and on the diaphragm. They typically appear 20 to 40 years after asbestos exposure. Unlike diffuse pleural thickening, plaques are localized and usually do not significantly affect lung function.
Symptoms
Pleural plaques usually cause no symptoms at all. Most are discovered incidentally on a chest X-ray or CT scan performed for an unrelated reason. When calcified, they are readily visible on imaging.
Are Pleural Plaques Dangerous? Do They Cause Cancer?
Pleural plaques themselves are benign — they are not cancer and do not turn into cancer or mesothelioma. However, they are an unmistakable indicator of asbestos exposure, and people with plaques have had the kind of exposure associated with an elevated risk of mesothelioma, asbestos-related lung cancer, and asbestosis. For that reason, a diagnosis of pleural plaques is a reason for ongoing medical monitoring, not alarm about the plaques themselves.
What They Look Like and When They Appear
Plaques are discrete, raised areas of fibrous thickening on the parietal pleura — the lining against the chest wall — most often over the lower ribs and the diaphragm. Over time many calcify, which makes them more visible on imaging and is why they are sometimes picked up incidentally on a scan taken for something else entirely.
They typically appear twenty years or more after first exposure, and CT detects them considerably more reliably than plain chest X-ray. They are the most common finding of any kind in people with a history of asbestos exposure.
What a Plaque Finding Does and Does Not Mean
It does mean asbestos fibres were inhaled, at a level and time sufficient to produce a physical change. That is documentation worth keeping.
It does not mean cancer is present or developing. Plaques themselves are benign, do not become mesothelioma, and in most people cause no symptoms and no measurable loss of lung function.
It does mean the exposure that caused them could also cause something else. Plaques are a marker of exposure, and exposure carries risk of mesothelioma, lung cancer and asbestosis — so their presence is a reason for a clinician to take new respiratory symptoms seriously rather than a reason for alarm in their own right.
Keep the report. If a malignancy appears years later, a dated record showing asbestos exposure already documented is materially useful both medically and legally.
Why They Matter
Because pleural plaques confirm asbestos exposure, they are medically and legally significant even without symptoms. If you are told you have pleural plaques, make sure your physician documents your asbestos-exposure history and establishes a monitoring plan, since your exposure carries longer-term risks that warrant watching.
If you were diagnosed with pleural plaques, mesothelioma, or another asbestos-related condition and were exposed to asbestos at work, in the military, or in a building, you may have a legal claim.
This information is educational, drawn from sources such as the American Cancer Society and National Cancer Institute, and is not medical advice. Consult your own physician about diagnosis and monitoring.