Pneumocystis Pneumonia : Microscopic Features

This image from a renal transplant recipient with pneumocystis pneumonia shows the classic features - foamy alveolar casts, type 2 pneumocyte hyperplasia, and moderate lymphoplasmacytic interstitial infiltrate. When the patient is immunosuppressed, the inflammatory response is usually limited. In cases with more vigorous immunologic reaction, it is usually granulomatous type.