Pulmonary infection caused by Gymnascella hyalinospora in a patient with acute myelogenous leukemia

We report the first case of invasive pulmonary infection caused by the ther motolerant ascomycetous fungus Gymnascella hyalinospora in a 43-year-old fe male from the rural midwestern United States. The patient was diagnosed wit h acute myelogenous leukemia and treated with induction chemotherapy. She w as discharged in stable condition with an absolute neutrophil count of 100 cells per pi. Four days after discharge, she presented to the Cancer Clinic with fever and pancytopenia. A solitary pulmonary nodule was found in the right middle lobe which was resected by video-assisted thoracoscopy (VATHS) . Histopathological examination revealed septate branching hyphae, suggesti ng a diagnosis of invasive aspergillosis; however, occasional yeast-like ce lls were also present. The culture grew a mold that appeared dull white wit h a slight brownish tint that failed to sporulate on standard media. The mo ld was found to be positive by the AccuProbe Blastomyces dermatitidis Cultu re ID Test (Gen-Probe Inc., San Diego, Calif.), but this result appeared to be incompatible with the morphology of the structures in tissue. The patie nt was removed from consideration for stem cell transplant and,ias treated for 6 weeks with amphotericin B (AmB), followed by itraconazole (Itr). A VA THS with biopsy performed 6 months later showed no evidence of mold infecti on. In vitro, the isolate appeared to be susceptible to AmB and resistant t o fluconazole and -5-fluorocytosine. Results for Itr could not be obtained for the case isolate due to its failure to grow in polyethylene glycol used to solubilize the drug; however, MICs for a second isolate appeared to be elevated. The case isolate was subsequently identified as G. hyalinospora b ased on its formation of oblate, smooth-walled ascospores within yellow or yellow-green tufts of aerial hyphae on sporulation media. Repeat testing wi th the Blastomyces probe demonstrated false-positive results with the case isolate and a reference isolate of G. hyalinospora. This case demonstrates that both histopathologic and cultural features should be considered for th e proper interpretation of this molecular test and extends the list of fung i recognized as a cause of human mycosis in immunocompromised patients.