Coccidioides immitis is a dimorphic fungus endemic to the arid areas of the southwestern United States and Central and South America. The C immitis organism grows as a filamentous mold in soil and as a parasitic form in human tissue. Although the saprobic mycelia form is rarely identified in human tissue, there have been very few reports of mycelial forms of the organism in specimens obtained from the respiratory and central nervous systems. To our knowledge, however, the presence of mycelial structures has not been reported in cutaneous lesions; we present the first case of numerous septate fungal hyphae found on histopathologic examination of a cutaneous lesion in a patient with disseminated coccidioidomycosis.
Kappel ST, Wu JJ, Hillman JD, Linden KG. Histopathologic Findings of Disseminated Coccidioidomycosis With Hyphae. Arch Dermatol. 2007;143(4):543-551. doi:10.1001/archderm.143.4.548