Phaeohyphomycotic cyst caused by Colletotrichum crassipes

A case of phaeohyphomycosis is reported in a male renal transplant recipient with a nodular lesion in the right leg who was treated with immunosuppressing drugs. The lesion consisted of a purulent cyst with thick walls. The cyst was excised surgically, and the patient did not receive any antifungal therapy. One year later he remains well. Histological study of the lesion showed a granulomatous reaction of epithelioid and multinucleate giant cells, with a central area of necrosis and pus. Fontana-Masson staining demonstrated the presence of pigmented hyphal elements. The fungus Colletotrichum crassipes was grown in different cultures from the cyst. The in vitro inhibitory activities of eight antifungal drugs against the isolate were tested. Clotrimazole and UR-9825 were the most active drugs. This case represents the first known reported infection caused by this rare species.