Two Cases of Lower Lobe Pneumatoceles Following Upper Lobectomy.

Postoperative pneumatocele is a rare complication of lung surgery. Here we describe 2 cases of pneumatoceles arising from the unaltered bottom part of the lower lobe a month or more after upper lobectomy. Based on histopathologic findings, we speculated that (1) negative pressure created by the volumetric gap between the thoracic cavity and the remnant lung and (2) increased positive pressure by the check valve mechanism from kinking or flexion of the airway after an upward movement of the remnant lung play crucial roles in the pathogenesis of postoperative pneumatoceles.