DQ stain, medium power:
Predominantly intracellular yeast forms with negative staining
DQ stain, high power:
Small, negatively staining extracellular yeast forms
Note one yeast with narrow based budding (yeast in middle)
Pap stain, high power:
Yeast forms inside macrophages
NOTE size variation: Some yeast smaller than lymphocyte nucleus and others larger
DQ stain, medium power:
Yeast forms with negative staining inside histiocytes
Note size variation of yeasts
GMS stain, high power:
Capsular retraction leading to halo, narrow based budding and size variation
Features
• Bronchioloalveolar lavage or washing
• Cerebrospinal fluid
Cryptococcus neoformans
• Predominant form: Yeast
• Size: Variably sized organisms, 0.5 - 2X the size of background RBC (4 -14 µm)
• Location: Intracellular (inside histiocytes) or extracellular
• Features:
– Thick, negatively staining capsule on Diff- Quik or Pap stain
– Pericapsular halo on GMS stain
– Narrow base budding