BAL: Pneumocystis jirovecii cyst (ascus) [wet mount preparation, phase contrast microscopy x1000]

Pneumocystis jirovecii cyst (also called ascus) in a spumous cluster observed in a bronchiolo-alveolar lavage (phase contrast microscopy) collected from an AIDS patient. Intracystic forms (or ascopores) appear as dark granules inside the thin-walled ascus