A farmer from Karnataka presents with a painless warty plaque on the foot present for 6 years. KOH mount shows brown, rounded, thick-walled 'muriform cells' (sclerotic bodies) dividing by cross-wall formation. The organism belongs to which group of fungi?
- A Dermatophytes (Trichophyton species)
- B Agents of chromoblastomycosis (dematiaceous/melanized fungi) ✓
- C Subcutaneous zygomycetes
- D Candida species
Explanation
Sclerotic bodies (Medlar bodies/muriform cells) — copper-coloured, thick-walled, multinucleate cells dividing in multiple planes — are the pathognomonic tissue form of chromoblastomycosis, caused by melanized (dematiaceous) fungi such as Fonsecaea pedrosoi, Cladophialophora carrionii, and Phialophora verrucosa. The melanin gives organisms their characteristic dark appearance. Dermatophytes cause tinea infections with hyphae and arthroconidia in skin. Zygomycetes cause mucormycosis with aseptate hyphae. Candida forms pseudohyphae or true hyphae in tissue, not sclerotic bodies.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.