A case of primary localized cutaneous infection due to Fusarium oxysporum

Fusarium is a ubiquitous hyalohyphomycete isolated from food, widespread in the environment (plants, soil) and present at all latitudes. Fusarium oxysporum and Fusarium solani are the most frequent pathogenic species, followed by F. moniliforme and F. chlamydosporum. Infections due to this mold may be disseminated or localized. Localized forms include cutaneous and subcutaneous infection, onychomycosis, endophtalmitis, otitis, sinusitis, arthritis, osteomyelitis, and brain abscess. Disseminated forms are those in which two or more noncontiguous sites may be involved. These latter are observed in patients with severe neutropenia. Wounds, digital ulcers, onychomycosis, and paronychia are the typical cutaneous portal of entry. We report a case of primary localized cutaneous infection due to Fusarium in a 29-year-old woman presenting with a nodular lesion, partially ulcerated, asymptomatic on the first finger of the left hand, appeared 4 months earlier. Histological examination showed spongiosis and acanthosis in the stratum corneum, ulceration and inflammation with prevalently mononucleate cells and septate and branched fungal structures in the epidermis and in dermis. The fungus was identified as Fusarium oxysporum by culture of biopsy fragments on Sabouraud dextrose agar with chloramphenicol. The culture was deposited in the culture collection of the mycology section of IHEM, Brussels (IHEM21984 col no. 125). The patient had normal immune status and was successfully treated with surgical excision. Recovery was confirmed at follow-up 8 months later.