A 45-year-old immunocompetent patient from Rajasthan presents with a chronic pulmonary nodule, skin ulcer over the hand, and draining sinus discharging black grains. Fungal culture of the grains on Sabouraud's medium grows dark, dematiaceous hyphae. Direct KOH shows characteristic 'copper penny' sclerotic bodies (muriform cells). The most likely diagnosis is:

• A Mycetoma (Madura foot) — Madurella mycetomatis
• B Sporotrichosis — Sporothrix schenckii (cigar-shaped yeast in tissue)
• C Chromoblastomycosis — Fonsecaea pedrosoi or Cladophialophora carrionii ✓
• D Lobomycosis — Lacazia loboi

Explanation

Chromoblastomycosis is characterized by the pathognomonic 'sclerotic bodies' (Medlar bodies / muriform cells / copper penny cells) — thick-walled, pigmented, septate fungal cells seen in tissue and direct KOH. They are NOT seen in mycetoma (which shows grains but not muriform cells). The causative agents are dematiaceous (black) fungi: Fonsecaea pedrosoi (most common), Cladophialophora carrionii, Phialophora verrucosa. Sporotrichosis shows cigar-shaped yeast. Treatment: itraconazole or voriconazole for chromoblastomycosis.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.