Pleural plaques seen by chance on a chest scan

What the report means

Where they are. Plaques form on the outer layer of the lining around the lungs (the parietal pleura), usually at the back and sides of the chest wall, on the dome of the diaphragm and near the middle of the chest. (Ferreiro 2025)
What they show. Plaques are treated as a marker that a person breathed in asbestos fibers in the past. When they are calcified, they are a typical sign of asbestos-related pleural scarring. (Ferreiro 2025)
How CT helps. A CT confirms plaques and can show whether there is wider pleural thickening or scarring in the lung itself (asbestosis). It also helps tell plaques apart from other causes such as old tuberculosis, past bleeding into the chest, rib fractures or, rarely, an early tumor of the lining. (Ferreiro 2025)
Symptoms. Plaques do not usually cause symptoms. Extensive plaques have sometimes been linked to chest pain, and studies show at most small differences in breathing test results. (Ferreiro 2025)

Why they show up later in life

Plaques usually appear 20 to 30 years after exposure, so they are mostly found in older adults. (Ferreiro 2025) The NHS notes asbestos was used in building from the 1950s to the 1990s. (NHS)
They are seen in more than half of workers directly exposed to asbestos, and less often in people exposed at home or nearby, such as people living with a worker who brought dust home on clothes. (Ferreiro 2025)
In a community study of 5,075 people in Iceland who had a chest CT, 7.9% had pleural plaques. The authors cite rates of 1.5% (Framingham Heart Study) and 3.9% (a US national survey) in other general populations, and 21% to 73% in highly exposed workers. (Ko 2026)
Many people do not know they were exposed. In one lung screening group selected for smoking, most people with plaques were unaware of past exposure. (ATS editorial 2020)

What usually comes next

A work and home history. Diagnosis rests on the scan and a history of exposure; sometimes a detailed job history is needed. (Ferreiro 2025) The National Cancer Institute says anyone exposed at work, in the environment or at home through a family member should tell their doctor about it. (NCI)
Follow-up is optional in many cases. A 2025 review says follow-up may end after diagnosis, or can be offered if the person is concerned. In Spain, a chest X-ray and a breathing test (spirometry) every 1 to 3 years is suggested. (Ferreiro 2025)
Low chance of change. The same review gives a 5% to 10% chance that plaques extend, 2% to 5% that wider pleural thickening develops, and 1% to 2% that mesothelioma (a cancer of the lining) develops, higher in some jobs with heavy exposure. (Ferreiro 2025)
Other findings on the same scan. Plaques are linked to small areas of lung scarring on CT. (Ko 2026) See lung scarring seen by chance on a chest CT and lung nodule found by chance.

Asbestos, plaques and lung cancer screening

Asbestos exposure raises the risk of lung cancer, and smoking together with asbestos exposure raises it more than the two risks added together. (NCI) MedlinePlus lists lung cancer, mesothelioma and asbestosis among the diseases that can follow heavy, long-term exposure. (MedlinePlus)

Plaques themselves. In a 2020 study of people with known moderate to heavy exposure, plaques did not add lung cancer risk once the amount of exposure was taken into account; an earlier French study did find a higher risk (hazard ratio 2.41). An editorial on the study says exposure, not the plaque, drives the risk, and that plaques should prompt a detailed exposure history where exposure is unclear. (ATS editorial 2020)
USPSTF. A yearly low-dose CT for adults 50 to 80 with a 20 pack-year smoking history who still smoke or quit within the past 15 years (grade B). Asbestos exposure and plaques are not part of these criteria. (USPSTF 2021)
NHS lung health checks. Offered in parts of England to people 55 to 74 who have ever smoked; a health professional asks about breathing, lifestyle, family and medical history to judge risk before offering a CT. (NHS lung screening)

See lung cancer screening, what to expect at a low-dose CT and lung cancer screening results.

Who it applies to

Adults told a chest X-ray or CT shows pleural plaques when the scan was done for another reason. The NHS names building and construction work, particularly from the 1950s to the 1990s, and today some work in old buildings, such as heating and ventilation, demolition, plumbing and electrical work. (NHS)

NHS, when to get medical help for possible asbestosis: (NHS)

See a GP if:

you have symptoms of asbestosis and think you've been exposed to asbestos

The NHS lists shortness of breath, a persistent cough, wheezing, extreme tiredness, and pain in the chest or shoulder as symptoms. (NHS)

Routine age-based screening

A finding on a chest scan does not replace the routine screenings for your age. See screenings by age and gender.

Where they differ:

Lung screening criteria. The USPSTF uses age 50 to 80 and a 20 pack-year history. (USPSTF 2021) The NHS uses age 55 to 74 and any smoking history, then a risk check. (NHS lung screening) The ATS editorial says screening policy largely focuses on smoking and does not fully address people with heavy asbestos exposure. (ATS editorial 2020)
Do plaques add risk? The 2020 Australian study found no added lung cancer risk from plaques after adjusting for exposure; the French study found a higher risk. (ATS editorial 2020) The 2025 review says people with plaques have a higher risk of more serious asbestos-related disease later. (Ferreiro 2025)
Follow-up. The 2025 review says follow-up may end after diagnosis, while the Spanish practice it cites suggests checks every 1 to 3 years. (Ferreiro 2025) The National Cancer Institute says a physical exam with a chest X-ray and breathing tests may be recommended for people with past exposure. (NCI)

Your doctor decides what your result means for you.

Questions people ask

Are pleural plaques cancer?

No. The National Cancer Institute says pleural plaques are not precursors to lung cancer. They are patches of scar-like tissue on the lining of the chest wall. (NCI) (Ferreiro 2025)

What causes them?

They are the most common sign of past asbestos exposure seen on scans and are treated as a marker of that exposure. They usually appear 20 to 30 years after exposure. Old injuries, tuberculosis and some other conditions can look similar, which a CT helps sort out. (Ferreiro 2025)

Will I need more scans?

Not always. A 2025 review says follow-up may end after diagnosis, or be offered if you are worried; in Spain a chest X-ray and breathing test every 1 to 3 years is suggested. Your doctor decides. (Ferreiro 2025)

Do pleural plaques make me eligible for lung cancer screening?

Not on their own. USPSTF criteria are age 50 to 80, a 20 pack-year smoking history, and still smoking or having quit within 15 years. NHS lung health checks are for people 55 to 74 who have ever smoked. Tell your doctor about any asbestos exposure. (USPSTF 2021) (NHS lung screening) (NCI)

What symptoms should I tell a doctor about?

The NHS says to see a GP if you have symptoms such as shortness of breath, a persistent cough or chest pain and think you have been exposed to asbestos. (NHS)