Asbestos-related rounded atelectasis. Radiologic and mineralogic data in 23 cases

A retrospective study was conducted in 23 subjects with previous occupational exposure to asbestos and exhibiting rounded atelectasis (RA) on high-resolution computed tomography scan (HRCT scan) to evaluate the retention of asbestos bodies (ABs) using light microscopy in the bronchoalveolar lavage (BAL) fluid or lung parenchyma in such patients. A total of 31 RAs were identified, usually located in the lower (25 RAs) and posterior (23 RAs) parts of the lung. Pleural thickening in contact with the RA was observed in 27 RAs and parenchymal bands were detected in 15 cases. Twelve of the 20 patients who underwent BAL or surgery exhibited significant retention of ABs in BAL fluid or lung tissue. Moreover, a significant retention of ABs was observed in five of nine patients with a history of asbestos exposure but no diffuse pleural thickening on chest radiograph or interstitial opacities on HRCT scan. Patients with RAs and coexisting diffuse pleural thickening and/or interstitial fibrosis should be considered at a higher risk for lung cancer in comparison to patients with isolated circumscribed pleural plaques based on increased AB counts. By contrast, the excess risk of lung cancer is more questionable in patients with only RAs and circumscribed pleural plaques as they may have AB counts either above or below that associated with pleural plaques alone. This emphasizes the need for further follow-up studies to define criteria indicating the need for thoracotomy in these subjects.