Multifocal cutaneous phaeohyphomycosis caused by Exophiala spinifera with clinical resolution in an immunocompromised cat.

Case summary: A 3-year-old neutered domestic shorthair cat with a long history of idiopathic immune-mediated haemolytic anaemia and thrombocytopenia treated with ciclosporin and prednisolone was referred 2 months after the appearance of nodular dermatitis. A single pigmented nodule was present in the lateral carpal region of the right foreleg. The lesion was 7 mm in diameter, non-exudative and cutaneous to subcutaneous. Fine-needle aspiration of the mass revealed the presence of pigmented fungal elements. Excisional surgery was planned; in the meantime, a plaque-like lesion developed in the interorbital region. Histopathological examination confirmed the presumptive diagnosis of phaeohyphomycosis, and Exophiala spinifera was identified as the aetiological agent. Itraconazole, given orally at a dose of 10 mg/kg for 8 weeks following surgery, enabled clinical resolution despite continued use of immunosuppressants. The follow-up was carried out over 14 weeks.

Relevance and novel information: This case report provides the first evidence of multifocal cutaneous phaeohyphomycosis caused by E spinifera with clinical resolution after combined surgical and itraconazole treatment in an immunocompromised cat.