Histoplasma capsulatum
These are oval-spherical in shape with a clear halo (that’s the capsule) invading neutrophils. There is also a sneaky nucleated red cell.
Pseudohyphae +/- budding can also be seen from the cells (use Gomori’s methenamine silver stain to highlight them)
Blastomyces dermatitidis and Cryptococcus neoformans looks similar
Also look for:
- Haemophagocytosis
- Increased plasma cells
- Granulomas
- STAINS: PAS+ and Prussian blue reaction +
If your patient has this, they are immunocompromised and therefore check HIV and the clinical details (e.g. immunosuppressive medication, primary immunodeficiency)
Image credit: www.photomacrography.net
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