Figure 1.

Characteristic globular alveolar casts of amorphous cyanophilic to acidophilic debris (a) are admixed with relatively scant cells (b). Some hyaline globules demonstrate two tone staining (c). The globules of variable sizes range in shapes and dimensions corresponding with alveolar spaces. Occasional pneumocytes may be seen "hugging" the periphery of globules (arrow in d). This is different from the frothy appearance of casts associated with P. carinii pneumonia which show individual vacuoles with central to eccentric dots. (Bronchoalveolar lavage; Papanicolaou stained SurePath Prep™).