- Asbestos-related pleural plaques represent focal areas of fibrotic response in the visceral pleura to previous exposure to inhaled asbestos fibres at least 8–10 years before. Classically, they calcify (approximately 50%). Both the presence of plaques and their calcification increase with time. They spare the costophrenic angles and lung apices. In their own right they have no malignant potential; however, in some patients, asbestos exposure can lead to pulmonary fibrosis, lung cancer and mesothelioma.
- Asbestos plaques are asymptomatic. Any chest symptoms should alert the clinician to the potential complications of asbestos exposure.
- CXR – focal areas of pleural thickening (<1 cm). They are usually bilateral and may be multiple. Plaques are more visible when they calcify and calcified plaques have a thicker peripheral edge than central portion. When they are seen en-face they have an irregular ‘holly leaf ’ appearance. Non-calcified plaques seen en-face can give a patchy density to the lungs. There should be no lymphadenopathy.
- They are associated with rounded atelectasis or pseudotumours. On the CXRthese look like peripherally based round nodules mimicking lung neoplasms. On CT imaging they demonstrate a rounded area of lung abutting an area of pleural thickening, with a swirl of vessels (tail) leading to the peripheral-based lesion. They are completely benign and should be recognised to avoid further invasive investigations.
- Occasionally the pleural thickening can be diffuse, restricting lung function and mimicking mesothelioma.
- There are few conditions which have a similar appearance.
- Previous history of TB or haemorrhagic pleural effusions can give a similar picture (more often unilateral).
- Exposure to amiodarone and a very rare condition of idiopathic pleural fibrosis can also produce these findings.
- No active management.
- Need to exclude complications of asbestos exposure with a supportive clinical history and possibly further imaging (CT scan).
- Consider follow-up, particularly if chest symptoms persist and the patient is a smoker. Pulmonary asbestosis (fibrosis secondary to asbestos exposure) increases the risk of lung cancer 40-fold if the patient is also a smoker.
- Consideration for industrial financial compensation.