[Rolled atelectasis and asbestosis. Apropos of 26 patients]

Round atelectasis (AE) is a benign form of respiratory problem which develops due to fixing of the visceral pleura. This lesion for which the principal cause is exposure to asbestos may pose problems of differential diagnosis with bronchopulmonary cancer. In a cohort of 286 patients suffering from benign asbestos related pleural disease the diagnosis of round atelectasis was made on computerized tomography in 26 patients (31 AE) on the following criteria: rounded opacities of less than 7 cm in diameter situated at the periphery of the lung in contact with a thickened pleura with an acute angle linking the pleura and the opacity, a reduction of lung volume on the side of the atelectasis and the presence of a "comet tail sign". These patients were investigated to specify the circumstances of the occurrence, including their symptomatology, the changes in lung function, the topography of the round atelectasis and the associated radiological signs. Intense exposure to asbestos either continuous or discontinuous was found in 19 patients; 20 patients presented with some respiratory symptoms (dyspnoea 15/26, cough 11/26 and chest pain 9/26) but the reduction in lung function was moderate (7 had restrictive ventilatory trouble, 4 obstructive problems and a mixed problem in 1). The preferred localisation for round atelectasis was in the inferior lobes in the posterior basal lateral vertebral area (26/31) which may explain their being frequently missed on the standard radiograph (only one case of round atelectasis was visible on the straight chest radiograph in our study). An understanding of the pathology and the computered tomographic characteristics are now well defined and should enable an unnecessary diagnostic thoracotomy to be avoided which besides has no justification from the functional point of view.