Rounded atelectasis (RA) is a focus of atelectatic subpleural lung parenchyma associated with infolding of the overlying pleura and scarring. RA can affect one or both lungs and may occur anywhere in the lung, but nearly one-half of cases are found in the lower lobes. Clinical associations include a history of previous exposure to asbestos, lymphangioleiomyomatosis, and status postsurgery for coronary artery disease, among others. Traditionally on chest x-rays, lung cancer was considered in the differential diagnosis of RA in patients with asbestos exposure.