Traumatic lung and paramediastinal pneumatoceles.

Traumatic pulmonary and paramediastinal pneumatoceles are definite, acutely formed, primary structural manifestations incident to nonpenetrating chest trauma. They are not secondary lesions, i.e., cavities or pneumatoceles resulting from the resolution of a pulmonary hematoma. Awareness of this fact will explain the not uncommon finding of a cavitary lesion, often containing an air-fluid level, on initial emergency room radiographs of patients who have sustained closed chest trauma. This will avoid unnecessary and unpleasant diagnostic procedures, including thoracotomy, for traumatic pneumatoceles are self-limiting, benign abnormalities which usually require no therapy other than observation.