Background Mesothelioma is an aggressive tumour of the pleura that is closely related to asbestos exposure. Asbestos is known to cause benign pleural thickening, effusion and plaques and the majority of patients with these abnormalities do not develop mesothelioma. It has been noted, however, that asbestos-exposed patients who have pleural plaques are at increased risk of mesothelioma.[1] This study aimed to describe the range of pleural abnormalities seen on CT done at some time before the diagnosis of mesothelioma was made.

Methods Electronic radiological records of all patients who were diagnosed with mesothelioma in the trust from 2009 till June 2017 were screened for any chest CT (or abdomen CT with at least half of the thorax imaged) obtained at least 6 months prior to the CT that triggered the diagnosis of mesothelioma. CTs were examined for the presence of pleural plaques, thickening, nodules and/or effusion. CT studies were divided into 3 time periods: within one year (A), 1–3 years before (B), and more than 3 years before (C) the diagnostic CT.

Results 170 patients were screened. 39 patients had one or more pre-diagnosis CTs. A total of 53 CTs were available for comparison. Effusion was the most common abnormality seen in 23/53 CTs followed by thickening seen in 17/53, then plaques 15/53 and pleural nodules in 5/53. Four nodules (2 in period A and 2 in period B) progressed to tumour later on. Effusion was seen in 50% of studies from periods A and B. Pleural thickening and plaques were noticeable in around 40% of CTs from periods A and B. 13 studies did not show any pleural abnormality (3 studies in period A, 4 in period B and 6 in period C).

Conclusion Mesothelioma is a rapidly progressive disease that can be difficult to track in radiological studies done before clinical presentation. Pleural effusion, followed by smooth thickening and plaques, are fairly common abnormalities in pre-diagnosis CTs.

Reference

1. Pairon J-C, Laurent F, Rinaldo M, et al. Pleural plaques and the risk of pleural mesothelioma. J Natl Cancer Inst 2013;105:293–301. doi:10.1093/jnci/djs513