Rounded atelectasis and its association with asbestos-induced pleural disease.

Rounded atelectasis (RA) is an unusual form of peripheral lobar collapse which may present as a juxtapleural mass simulating a pulmonary neoplasm. Seven cases of RA were recently encountered in patients with asbestos-induced pleural disease. Since asbestos exposure is associated with mesothelioma, bronchogenic carcinoma, and other tumors, differentiation of RA from these neoplasms is essential in avoiding unnecessary thoracotomy. The radiographic features of RA are sufficiently characteristic, so that in the presence of chronic pleural thickening due to asbestos exposure, the diagnosis can be made with assurance and further work-up avoided.