Rare case of aspergillosis with solitary renal involvement: micro-fungus ball in graft kidney.

Kidney transplant recipients are at an increased risk of various infections due to immunosuppressive medications. Among them, fungal infections are associated with high mortality and morbidity. This report presents the case of a 54-year-old kidney-transplant recipient who was diagnosed with aspergillosis with solitary renal involvement. He was diagnosed by kidney biopsy with the micro-fungus ball. In the biopsy sample, consisting mostly of the medulla, a small focus consisting of an aggregate of fungal microorganisms was identified. The micro-fungus ball, which was also present in serial sections, was characterized by slight pigmentation and septate hyphae with acute angle branching, highlighted by the silver stains. The patient was examined for invasive fungal infection. In CT scans, there were no signs of invasive fungal infection. Due to the unexpected kidney biopsy finding, the patient underwent a repeat allograft biopsy from which a culture was sent. Aspergillus fumigatus complex was detected in tissue fungal culture of this repeat biopsy. The patient was started on voriconazole treatment and was successfully treated. It should be kept in mind that fungal infections with isolated subtle renal involvement may be possible in KTR under immunosuppressive treatment without an obvious fungal focus being demonstrated by imaging methods.