Histoplasma capsulatum in a peripheral-blood smear.

Figure 1. A 45-year-old man with the acquired immunodeficiency syndrome presented with night sweats, fatigue, cachexia, and a productive cough. He had a fever (temperature, 40°C), tachycardia (heart rate, 136 per minute), a leukocyte count of 2.5×103 per cubic millimeter, and hypotension (blood pressure, 90/50 mm Hg). A chest x-ray film revealed an infiltrate in the right lower lobe. A peripheral-blood smear (Wright's stain, ×1000) obtained on admission showed a monocyte with a grossly distorted nucleus and numerous intracellular yeast-like organisms 2 to 4 μm in diameter with eccentric chromatin. The organisms were surrounded by an artifactual pseudocapsule caused by . . .