Athlete's Foot Research Today is a free monthly online journal that collates and summarizes the latest research about Athlete's Foot, including details on tinea, causes, treatment, prevention.

Pseudomycetoma caused by Microsporum canis in an immunosuppressed patient: a case report and review of the literature.

Berg JC, Hamacher KL, Roberts GD

Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA.

BACKGROUND: A 65-year-old woman with a history of liver and kidney transplantation presented with a pruritic and tender rash of 2-year duration on her left knee. METHODS: The patient had a physical examination, and multiple skin biopsies were performed. RESULTS: Examination showed a cluster of dome-shaped, violaceous papules. A skin biopsy specimen showed multiple granules containing basophilic material within the superficial to mid dermis. The grains were embedded in an eosinophilic substance and surrounded by granulomatous inflammation. A Gomori methenamine silver stain showed abundant septate hyphae, and cultures grew colonies of Microsporum canis. A diagnosis of dermatophytic granuloma, or pseudomycetoma, was made. After considering the patient's immune status, a prolonged course of fluconazole was initiated. CONCLUSION: Microsporum canis, a frequently encountered zoophilic dermatophyte associated with tinea capitis and tinea corporis, is rarely associated with a mycetoma-like presentation, grain formation, or systemic infection. The medical literature describes only six cases of M. canis causing mycetoma-like formations in immunocompromised and immunocompetent patients. This case report describes an unusual presentation of a common dermatophyte infection, and the literature review summarizes the importance of recognizing atypical presentations of dermatophyte infections. Such infections may warrant more aggressive treatment in immunocompromised patients.

Published 23 April 2007 in J Cutan Pathol, 34(5): 431-4.
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