Rounded atelectasis: considerations on its radiological diagnosis.

Rounded atelectasis is a particular form of peripheral lung collapse, adjacent to the pleura and causing a pulmonary opacity, often resembling a neoplastic mass. Its early identification avoids further investigations with more invasive techniques, especially unnecessary thoracotomy. The aim of this report is to contribute some case studies to the body of information which characterizes this radiographic and tomodensitometric entity; aspiration biopsy can possibly be performed to resolve diagnostic uncertainties.