Exophiala spinifera as a cause of cutaneous phaeohyphomycosis: Case study and review of the literature

Abstract

Exophiala spinifera has been reported as an agent of cutaneous disease 18 times in the literature. Clinical presentations of cutaneous lesions vary widely, including erythematous papules, verrucous plaques, and deep subcutaneous abscesses. The clinical distribution and course of disease are also variable, depending on the age and immune competency of the patient. Histologic appearance occurs in one of two patterns - phaeohyphomycosis or chromoblastomycosis. While E. spinifera appears to be susceptible to multiple antimicrobial agents in vitro, clinical experience with treatment modalities has been variable. Prior to the availability of sequencing methods, species identification was based on the histopathologic presentation in tissue and morphologic features of the fungus in culture. It is likely that E. spinifera cutaneous infections have been underreported due to its incorrect identification based on earlier methods. We report an additional case of E. spinifera phaeohyphomycosis, the first to be definitively identified by sequencing. In addition, we summarize the variable clinical, histopathologic, and morphologic features, as well as treatment responses described in previously reported cutaneous infections caused by E. spinifera.