Pleural plaques consist of bordered areas of grey-white hardened fibrous – tissue, and commonly appear on the ‘parietal pleura’ and found less frequently on the ‘visceral pleura’.
The first recognition of pleural plaques in connection with workers exposed to asbestos was made by J.B Sparks in 1931, who recorded them as ‘irregular calcified plaques’. Pleural plaques usually appear 2-3 decades after initial asbestos exposure, and x-ray results will be largely dependent on the denseness of the plaques, and therefore scarring may go undetected during routine tests, whereas a CT scan has the ability to detect 60% more plaques. An even higher result may also be obtained using a high resolution CT scan.
Parietal pleural plaques:
Parietal pleural plaquesare most frequently found along the 6th to the 9th ribs and along the diaphragm and can vary in size, i.e. visible to the naked eye or up to 12cm in length. Their surface may appear flat or consist of 4-5mm multiple nodules and the density of the plaques can vary between 2mm – 1cm, or more.
Visceral pleural plaques:
Visceral pleural plaques as mentioned are considerably less common and can be found within the peritoneum, and on the surface of the spleen or liver, and on rare occasions may involve the pericardium.
Visceral pleural Symptoms:
Symptoms rarely occur with pleural plaques and they are usually detected on a routine x-ray. The lack of symptoms has led to a controversial argument regarding whether plaques can be classed as a disease and therefore warrant compensation. However -asbestos campaigners point out that; although plaques appear to be none symptomatic the damning uncertainty as to whether the plaques will develop into a more serious asbestos related disease such as mesothelioma, and asbestosis.
Conclusive evidence – the role of asbestos in the formation of pleural plaques:
Public health studies have concluded that inhaled asbestos fibres (particularly amphibole) have been found in the lungs of patients with plaques. . . If you need more insight for yourself or loved ones, visit mesothelioma.net for further information and support. Calcification and lesions occur when surplus connective tissue builds up in an area where the bodies natural defenses attempts to repair structural damage. Although pleural plaques cannot be assumed to be a precursor for mesothelioma, more incidences of pleural plaques have been detected among mesothelioma patients, amounting to an 11- fold increased risk of developing mesothelioma.