Objectives: The most common imaging characteristics of a high-grade glioma can be emulated by rare entities of a different nature, an issue which should always be kept in mind. This case report aims to underline that fact and present a rare differential diagnosis.

Case report: A 61 year-old female with an unremarkable medical history presented with paraphasia, which had been worsening over a few weeks. MRI showed a large left temporal, ill-defined lesion with heterogeneous signal intensity on both T1W and T2W images, and heterogeneous contrast enhancement, surrounded by edema, suggestive of a high-grade glioma. Surgery was performed, and both the intraoperative brain tissue appearance and pathology were negative for neoplastic tissue, but suggestive of chronic inflammation. Two months later, language disturbances worsened, and a repeat MRI revealed progression to a wider lesion. In the absence of a definitive diagnosis, a second surgical approach was undertaken. Pathological examination now suggested, additionally, chronic non-granulomatous vasculitis. No microorganisms were directly identified. After specific DNA probing, Aspergillus fumigatus was found present in both the biopsy tissue and peripheral blood samples.

Discussion: Aspergillus fumigatus is a common fungus that rarely infects the CNS. It can present as meningitis, intracranial aneurysms, multiple infarctions, hemorrhage or space-occupying granulomas. Immunocompromised patients are more commonly infected, although there have been several reports in immunocompetent patients, usually presenting in these cases as a mass lesion. Due to its unspecific imaging appearance and rare central hyphae on histology, intracerebral aspergillosis poses a real diagnostic challenge.