Subcutaneous phaeohyphomycosis caused by Exophiala equina, with susceptibility to eight antifungal drugs

A case of subcutaneous phaeohyphomycosis caused by Exophiala equina is reported in a 75-year-old female, who showed subcutaneous abscesses on both forearms for 8 months. A lesion was initiated by inoculation with a spine from a tree. Histopathologically, suppurative granulomatous inflammation was present and short hyphal elements were observed. Upon culture greyish-black, velvety colonies of a black yeast were obtained after 3 weeks. The strain grew well at 25 °C, but poorly at 37 °C. After sequencing the internal transcribed spacer domain and the partial β-tubulin gene, the fungus was identified as E. equina. The patient was successfully treated with fluconazole for 3 months.