A case of pseudoparacoccidioidomycosis: detection of the yeast phase of Mucor circinelloides in a clinical specimen.

A case is presented in which yeastlike cells resembling the yeast phase of Paracoccidioides brasiliensis were observed by microscopic examination of a urine sample. A mold identified as Mucor circinelloides was isolated from the specimen. It was converted to the yeast form by cultivation on Sabouraud agar incubated in a GasPak jar at 37 degrees C. The isolate was eventually shown not to be related to the patient's illness; however, the superficial resemblance of the yeast phase to P. brasiliensis caused some confusion in making a correct diagnosis.