Chromoblastomycosis is a chronic systemic fungal disease, acquired in the cutaneous form by traumatic or imperceptible implantation, and characterized by ulcerated, crusted lesions of the skin and subcutaneous tissues.
History of Chromoblastomycosis
Although rare in this country, chromoblastomycosis was first reported from Boston in 1915, separately by Lane and Medlar, and the organism responsible was named Phialo-phorja verrucosa by Thaxter. Subsequently, cases owing to other genera of fungi were described by Brumpt and Carrion. The first case of cerebral disease was reported in 1948 by Bonne.
Etiology of Chromoblastomycosis
A number of fungi have been incriminated, but chiefly Phialophora verrucosa, P. pedrosoi, P. compactum, and Cladosporium car-rionii. In tissues these fungi resemble each other and appear as single or clustered, round, thick-walled, 6 to 12 p. budding cells of a striking brown color, from which the disease draws its name. On culture, mycelia are produced that vary according to genus and species. Skin hypersensitivity and complement-fixing antigens have been demonstrated in some fungal species. Laboratory animals are susceptible to experimental infection, but the equivalent of natural disease in man is not produced.
Epidemiology of Chromoblastomycosis
The disease is seen more often in adult males in the rural areas of the tropics, especially in Brazil, Puerto Rico, and Cuba. The responsible fungi are saprophytes of soil, but are found more often in decaying wood and vegetation. Infection in animals has not been reported, and animal-to-man or man-to-man spread is unknown.
Pathology. Varying degrees of hyperkeratosis, acanthosis, and pseudoepitheliomatous hyperplasia are seen. In the cutis the reaction may be granulomatous with mononuclear, epithelioid, and Langhans’ giant cells. Fungal cells are seen readily with hematoxylin and eosin stains.
Clinical Forms of Chromoblastomycosis
Chromoblastomycosis is a disease of the skin and subcutaneous tissue.The first patient reported had lesions of the buttock. The most common site is the lower extremity. The disease appears also, in descending order of frequency, on the hand, forearm, arm. neck, and shoulders. The earliest lesion is a nodule or pustule that, over a period of weeks to months, ulcerates, drains, enlarges, dries, and becomes violaceous and wartlike. There is rarely pain, but itching is common. Lesions do not spread generally, but scratching results in autoinoculation and satellite or secondary distal lesions.
Diagnosis of Chromoblastomycosis
Although older typical skin lesions may be clinically and histologically suggestive, the diagnosis is confirmed by the culture and identification of the causative organism.Early lesions may be confused with blastomycosis, tuberculosis, leprosy, yaws, and syphilis.
Treatment of Chromoblastomycosis
Surgical resection of early skin lesions has been the most common and efficacious therapy. Amputation has been required in a small number of cases. Most of the fungi causing chromoblastomycosis are resistant to amphotericin B, but successful treatment has been reported in two cases when the drug was injected locally into the skin. This drug needs further trial in this disease.
Prognosis of Chromoblastomycosis
The cutaneous form of chromoblastomycosis is chronic and compatible with long life (in one case, 40 years).