[A round atelectasis that development 7 years after the start of follow-up].

A 60-year-old man was admitted to the hospital because of dyspnea on exertion in November 1990. He had a history of asbestos exposure and chest CT scans showed bilateral pleural thickening with calcification and oval-shaped consolidation in the right lower posterior lung field. A chest CT scan obtained in May 1994 showed that the shadow had become smaller and more round. Its size continued to decrease, and in June 1997 the "comet-tail sign" was observed. This is the longest interval between initiating of follow-up and development of round atelectasis yet reported.