Subpulmonic pneumothorax in patients with chronic obstructive pulmonary disease.

A spontaneous pneumothorax is occasionally seen under the lung on upright views, apparently due to subpulmonic trapping of pleural air by adhesions. This is most likely to occur in patients with chronic obstructive pulmonary disease (COPD), especially if they have extensive parenchymal scarring from previous tuberculosis. The authors describe 4 patients who had subpulmonic pneumothorax, severe COPD, and parenchymal scarring and presented in respiratory failure. None had other clinical symptoms suggesting pneumothorax. Radiologists should be aware of this condition, since it is potentially lethal.