[Pneumothorax caused by histiocytic pneumonitis]

Specimens from the lung obtained during the treatment of spontaneous pneumothorax revealed a hitherto unknown histological phenomenon characterised by a histiocytic, inflammatory interstitial pulmonary tissue containing gas. By following the course of the gas an intracellular pathogen could be identified in the macrophages. Its shape resembled that of micrococci, ist size was between 2-4 microns. The ultrastructure within the pathogen suggested gas formation. In these cases the origin of the pneumothorax was attributed to the aerogenous microorganism that had induced a phagocytic inflammation in the pulmonary tissue.