[Round atelectasis].

The authors report 4 cases of round atelectasis seen over a period of 3 years. They review the very limited literature on this subject. In the light of their experience and according to the work of Hanke, they believe this to be a fairly common disease. This condition was first described during collapsotherapy, but now, it is essentially seen following pleurisy. For Hanke, round atelectasis may occur in almost one quarter of cases of pleural effusion. The authors also believe that this condition is common and that it is usually confused with or grouped together with "pleural sequelae". However, their original mechanism of formation, the reversible parenchymal involvement, and not pleural, and their radiological appearance clearly distinguish them. Round atelectasis is an interesting topic of discussion in terms of diagnosis, in the broad framework of round intrathoracic opacities (especially when the initial pleural episode has not been recognized) and also in terms of treatment, which consists of decortication when they are large.