Subcutaneous phaeohyphomycosis caused by Xylohypha emmonsii

The first human phaeohyphomycotic infection caused by Xylohypha emmonsii is described. The patient, an 83-year-old woman, developed a purpuric lesion on her left arm. The pale brown fungal elements observed in biopsy tissue consisted of thin- to thick-walled, oval to spherical, yeastlike cells with single and, occasionally, multiple buds; chains of budding cells; cells with internal septations in one and, rarely, two planes; and septate hyphae. In culture, X. emmonsii grew moderately fast at 25 degrees C, showed minimal growth at 37 degrees C, and failed to grow at 40 degrees C. It produced acropetal chains of one-celled (rarely two-celled) conidia laterally and terminally directly from vegetative hyphal cells.