Phaeohyphomycosis

Phaeohyphomycosis is characterized by pig­mented hyphae in tissue. Various black molds may be causative, including Alternaria, Bipolaris, Curvularia, Exophiala, and Phialophora. In immunocompetent hosts, direct inoculation due to trauma or a splinter is the most common cause, resulting in a pseudocyst lined by histiocytes and giant cells containing pigmented hyphae. Immunocompromised patients are more likely to develop disseminated lesions that lack the pseudocystic architecture.