Pathologic Aspects of Atypical Pneumonias

(Interstitial Pneumonitis)

¹ The Department of Pathology and Bacteriology, Marquette University School of Medicine, Milwaukee, Wisconsin.

The interstitial pneumonitis due to a variety of etiologic agents and circumstances has been commented upon to emphasize certain aspects not commonly stressed, namely, the common hyperplasia and metaplasia of alveolar and bronchiolar lining cells, and the tendency in many cases to progress to interstitial fibrosis. The changes which often cause cyanosis to be a prominent clinical feature would merit a separate complete and full discussion. One may speculate as to whether the present prevalence of atypical pneumonia may lead in the future to an increased clinical incidence of (1) effects of interstitial pulmonary fibrosis, and (2) pulmonary tumors resulting from stimulation of bronchiolar and alveolar lining cells. Only time will give the answer.