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Phaeohyphomycosis due to Alternaria spp. and Phaeosclera dematioides: a histopathological study
J Pec1, E Palencarova, L Plank
1Department of Dermatology, University Hospital, Slovak Republic.
Abstract:
A case of phaeohyphomycosis caused by strains of both Alternaria spp. and Phaeosclera dematioides is presented. The biopsy material was studied using histological, immunohistochemical and transmission electron microscopy techniques. The agent's dematiaceous mycelia are composed of thick-walled hyphae, branched and unbranched, with terminal vesicular formations. All the described structures occur alone or in chains within multinuclear giant foreign body-type cells or invading an abscess. Also present are budding forms. Immunostaining of histiocytic inflammatory cells in either. diffuse or granulomatous infiltrates revealed cytoplasmic positivity for lysozyme and Ki-MIP antibody. The lymphocytic infiltrates of the upper corium show predominantly small T lymphocytes (CD3 and CD45RO positive) and absence of CD20-positive B cells. Plasma cells occurring within the infiltrates of the deeper parts show polyclonal expression of both Ig light chains.
Insights
This study details a rare phaeohyphomycosis case caused by Alternaria spp. and Phaeosclera dematioides. Advanced microscopy revealed fungal elements within inflammatory cells, aiding diagnosis.
Area of Science:
- Medical Mycology
- Dermatopathology
- Immunohistochemistry
Background:
- Phaeohyphomycosis is a fungal infection caused by dematiaceous fungi.
- Co-infection with multiple fungal species is uncommon.
Observation:
- Biopsy analysis revealed dematiaceous mycelia of Alternaria spp. and Phaeosclera dematioides.
- Fungal elements were observed within multinuclear giant cells and abscesses.
- Histological, immunohistochemical, and transmission electron microscopy techniques were employed.
Findings:
- Immunostaining identified lysozyme and Ki-MIP positivity in histiocytic inflammatory cells.
- Lymphocytic infiltrates showed CD3 and CD45RO positive T lymphocytes.
- Absence of CD20-positive B cells and polyclonal Ig light chain expression in plasma cells were noted.
Implications:
- This case highlights the diagnostic utility of advanced microscopy and immunohistochemistry in complex fungal infections.
- Understanding the host immune response is crucial for managing phaeohyphomycosis.
- The findings contribute to the knowledge of fungal pathogenesis and host-cell interactions.