[Round atelectasis: infrequent cause of solitary pulmonary nodule].

Two cases of round atelectasis are reported. One had an asbestiform origin, with lingular localization and pathological confirmation. The other was located in the posterobasal segment of the left lower lobe, and it was presumably caused by pleural tuberculosis. In both patients the characteristic radiological findings were present, with an outstanding "comet's tail" sing. The outcome of both patients was satisfactory. Emphasis is made on the usefulness of noninvasive diagnostic investigations, such as conventional pulmonary and computed tomography (CT) of the torax, which, in conjunction with an adequate anamnesis, permit the correct diagnosis and may prevent surgical exploration.