A farmer presents you with a cauliflower-shaped mass on foot, which developed after a minor injury. Microscopy shows copper penny bodies. What is the most likely diagnosis?

Correct Answer: C. Chromoblastomycosis

Chromoblastomycosis is a chronic subcutaneous mycotic infection caused by dematiaceous (pigmented) fungi, classically presenting with a cauliflower-shaped mass on the foot following minor trauma. The pathognomonic histological finding is copper penny bodies (also called sclerotic bodies or medlar bodies)—thick-walled, dark brown, septate fungal cells that appear as round structures resembling copper coins under microscopy. These are the hallmark of chromoblastomycosis and distinguish it from other mycoses. The disease is endemic in tropical and subtropical regions, including India, and predominantly affects agricultural workers and farmers with soil exposure. The fungi (commonly Fonsecaea pedrosoi, Cladophialophora carrionii, or Phialophora verrucosa) enter through minor cuts or abrasions and cause a slowly progressive, verrucous, nodular lesion that may eventually ulcerate. The diagnosis is confirmed by demonstrating copper penny bodies in tissue sections or culture on Sabouraud's dextrose agar. Treatment typically involves itraconazole or terbinafine, though surgical excision may be needed for localized lesions.

Why the other options are wrong

A. Phaeohyphomycosis — Phaeohyphomycosis is caused by dematiaceous fungi but presents with brown septate hyphae in tissue, not copper penny bodies. While both involve pigmented fungi, phaeohyphomycosis typically manifests as subcutaneous cysts or abscesses rather than the characteristic cauliflower-shaped verrucous lesion. The absence of sclerotic bodies rules this out. B. Sporotrichosis — Sporotrichosis (caused by Sporothrix schenckii) presents with a lymphocutaneous pattern (rose gardener's disease) with nodular lymphangitis, not a solitary cauliflower mass. Histology shows asteroid bodies (yeast forms surrounded by eosinophilic material), not copper penny bodies. The clinical presentation and microscopic findings are distinctly different. D. Blastomycosis — Blastomycosis is caused by Blastomyces dermatitidis and presents with broad-based budding yeast on histology, not copper penny bodies. It is rare in India and typically presents with pulmonary symptoms or disseminated disease. The absence of sclerotic bodies and the endemic pattern in North America make this unlikely in an Indian farmer.

High-Yield Facts

Mnemonics

COPPER PENNY = Chromoblastomycosis Cauliflower + Copper penny bodies + Chronic = Chromoblastomycosis. Remember: copper = dematiaceous (pigmented) fungi; penny = round sclerotic bodies. FARM FOOT FUNGUS (FFF) Rule Farmer + Foot + Fungus with cauliflower lesion = think Chromoblastomycosis. Soil exposure + minor trauma = dematiaceous fungi entry.

NBE Trap

NBE may pair "cauliflower lesion" with sporotrichosis (rose gardener's disease) to trap students who confuse cutaneous mycoses. The discriminator is the copper penny bodies on histology—unique to chromoblastomycosis—and the solitary verrucous mass rather than lymphocutaneous spread.

Clinical Pearl

In rural India, a farmer presenting with a slowly enlarging, warty, nodular lesion on the foot or hand after a thorn prick or minor injury should raise immediate suspicion for chromoblastomycosis. Early diagnosis via KOH mount or biopsy showing copper penny bodies allows timely systemic antifungal therapy and prevents progression to ulceration and secondary infection.

_Reference: Robbins Ch. 8 (Infectious Diseases); Harrison Ch. 212 (Fungal Infections); Park's Textbook of Preventive and Social Medicine (endemic mycoses in India)_