Sclerotic Bodies: Chromoblastomycosis vs Phaeohyphomycosis
Original bench-card visual contrasting muriform sclerotic bodies in tissue with dematiaceous septate hyphae, the split that separates chromoblastomycosis from phaeohyphomycosis.
Dematiaceous tissue forms: sclerotic bodies vs pigmented septate hyphae
Many dematiaceous molds look alike in culture. The tissue form is what splits the disease: clustered muriform sclerotic bodies point to chromoblastomycosis, while pigmented septate hyphae point to phaeohyphomycosis.
Thick-walled brown cells in clusters, divided by septa in more than one plane (muriform). Often called copper pennies. This tissue form defines chromoblastomycosis.
Brown septate hyphae, sometimes with budding yeast forms. Pigmented hyphae in tissue point to phaeohyphomycosis rather than chromoblastomycosis.
Thick-walled brown cells in clusters, divided by septa in more than one plane (muriform). Often called copper pennies. This tissue form defines chromoblastomycosis.
Brown septate hyphae, sometimes with budding yeast forms. Pigmented hyphae in tissue point to phaeohyphomycosis rather than chromoblastomycosis.
Tissue-form anchors
| Visual clue | Meaning | Student shorthand |
|---|---|---|
| Clustered muriform brown cells | Sclerotic bodies | Septa in two planes; copper-penny look defines chromoblastomycosis |
| Brown septate hyphae in tissue | Phaeohyphomycosis form | Pigmented hyphae, sometimes with yeast forms |
| Visible brown pigment without stain | Dematiaceous group | Pigment is present on H&E and on Fontana-Masson |
| Subcutaneous or sinus source | Clinical context | Significance depends on source and host; interpret per SOP |
Tissue-form interpretation guide
| Pattern | What to call it | How to think about it |
|---|---|---|
| Muriform sclerotic bodies in tissue | Chromoblastomycosis | Correlate with culture; report tissue form per SOP |
| Pigmented septate hyphae or yeast in tissue | Phaeohyphomycosis | Correlate with culture and clinical source |
| Faint or absent visible pigment | Confirm melanin | Fontana-Masson stain supports a dematiaceous process |
- Tissue form, not genus, separates chromoblastomycosis from phaeohyphomycosis.
- Sclerotic bodies are clustered, muriform, and thick-walled.
- Fontana-Masson confirms melanin when pigment is hard to see.
Sclerotic bodies = chromoblastomycosis. Pigmented hyphae = phaeohyphomycosis.