Misleading Manifestations of Coccidioides immitis In Vivo

Abstract

ABSTRACT We describe a case of coccidioidomycosis in which several unusual morphologic forms of Coccidioides immitis occurred in biopsy tissue from the right lower lung of a patient. To our knowledge, this is the first case where so many diverse morphologic forms were manifested in a single patient in the absence of typical endosporulating spherules. Immature spherules demonstrating segmentation mimicked morula forms of Prototheca spp. Certain elements resembled budding cells of Blastomyces dermatitidis . These consisted of juxtaposed immature spherules without endospores, a germinating endospore, or thick-walled hyphal cells. Branched, septate hyphae and moniliform hyphae consisting of chains of thick-walled arthroconidia or immature spherules were also present. Complement fixation and immunodiffusion tests performed on the patient’s serum were negative for C. immitis , B. dermatitidis , and Histoplasma capsulatum antibodies. Fluorescent-antibody studies were carried out with a specific C. immitis conjugate. All of the diverse fungal tissue elements stained positive with a moderate to strong (2 to 3+) intensity.