Which histologic findings are characteristic of fungal pneumonia?

Updated: Jun 21, 2019
  • Author: Romeo A Mandanas, MD, FACP; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Answer

Answer

Histopathology findings are as follows:

  • Aspergillosis: Nonpigmented (hyaline), septate hyphae with acute angle branching, but not specific
  • Mucormycosis: Nonpigmented (hyaline), broad non-septate hyphae presumptive evidence for mucormycosis
  • Cryptococcosis; Yeast forms with clear surrounding area are suggestive; mucicarmine stain is specific
  • Blastomycosis: Broad based budding yeast (10-15 µm); forms provide presumptive evidence of infection
  • Histoplasmosis: Small yeasts (2-4 µm) with narrow-based budding grouped in clusters inside macrophages; characteristic yeast forms provide presumptive evidence of infection
  • Coccidioidomycosis: Spherules large and specific, give presumptive diagnosis
  • Candidiasis: Small yeasts (3-5 µm) intermingled with pseudohyphae and/or hyphae; C glabrata does not produce filaments or pseudohyphae
  • Sporotrichosis: Dimorphic fungus, conidiophores, and conidia; cigar-shaped yeast may be visualized in tissue specimens stained with periodic acid-Schiff, Gomori methenamine-silver, or immunohistochemical stains
  • Scedosporium: Haphazardly branching hyphae and lemon-shaped conidia; parallel hyphae bridged at right angles producing letter-H patterns; purple conidia in tissue [34]

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