Rhizopus arrhizus and Fusarium solani Concomitant Infection in an Immunocompromised Host.

Neutropenic patients are at risk of the development of hyalohyphomycosis and mucormycosis. Correct identification is essential for the initiation of the specific treatment, but concomitant mold infections are rarely reported. We report one unprecedented case of concomitant mucormycosis and fusariosis in a neutropenic patient with acute myeloid leukemia. The patient developed rhino-orbital infection by Rhizopus arrhizus and disseminated infection by Fusarium solani. The first culture from a sinus biopsy grew Rhizopus, which was consistent with the histopathology report of mucormycosis. A second sinus biopsy collected later during the patient's clinical deterioration was reported as hyalohyphomycosis, and the culture yielded F. solani. Due to the discordant reports, the second biopsy was reviewed and two hyphae types suggestive of both hyalohyphomycetes and mucormycetes were found. The dual mold infection was confirmed by PCR assays from paraffinized tissue sections. Increased awareness of the existence of dual mold infections in at-risk patients is necessary. PCR methods in tissue sections may increase the diagnosis of dual mold infections. In case of sequential biopsies showing discrepant results, mixed infections have to be suspected.