Figure 3b. P carinii pneumonia in a 32-year-old man with acquired immunodeficiency syndrome. (a) High-resolution CT scan shows areas of ground-glass attenuation with intralobular lines. (b) Photomicrograph (original magnification, x400; Grocott stain) of a specimen obtained with bronchoalveolar lavage shows alveolar exudates that contain cystic forms of P carinii (arrows).