A patient in their 20's presents with non-healing wounds and tissue necrosis, 1 month after left thigh radical soft tissue and femur resection and total femoral replacement endoprosthesis. The patient has a past medical history significant for slipped capital femoral epiphysis status post total hip arthroplasty, with recent diagnosis of high-grade left thigh osteosarcoma, with pulmonary metastases and multiple deep vein thromboses of the left lower extremity. The osteosarcoma has been unresponsive to chemotherapy, warranting the recent surgery.
For limb salvage, the patient sequentially underwent 2 rounds of left thigh irrigation and debridement, of which deep wound cultures were taken. Four surgical swabs were sent to the lab for bacterial, acid fast bacterial and fungal stain and culture. Fungal elements were seen on 2 specimen fungal stains, and bacterial and fungal culture results were reported out as yeast.
MALDI-TOF mass spectrometry failed to identify the yeast isolate after 2 attempts. Performance of carbon assimilation tests also yielded no identification. The infectious disease team urgently awaited organism identification. Wound healing complications and concerns for invasive disease further delayed administration of the patient’s chemotherapy regimen.
At 3-4 days of growth, the organism appeared as spindle-shaped budding yeast cells under the microscope. At 6 days, the colonies appeared drier and more wrinkled, with young hyphal growth seen at the periphery. Branching filaments with possible arthroconidia were observed under the microscope. At 7-8 days, the colonies had grown together exhibiting a powdery and cerebriform appearance. Rectangular arthroconidia were seen under the microscope.
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Author InformationJune L. Chan, Ph.D., University of California Los Angeles
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