Invasive cerebral phaeohyphomycosis in a Chinese boy with CARD9 deficiency and showing unique radiological features, managed with surgical excision and antifungal treatment.

• Isolated cerebral phaeohyphomycosis may require a focus on CARD9 deficiency. • Radiological imaging alone cannot differentiate cerebral fungal lesions from tumors. • Paired CSF and serum voriconazole levels are useful in treating cerebral fungal infection. We report this rare case of cerebral phaeohyphomycosis in a previously healthy Chinese boy, who was found to have caspase recruitment domain family member 9 (CARD9) deficiency. Initial radiological features suggested a neoplastic cerebral lesion, while histopathological examination supplemented by internal transcribed sequencing (ITS) of cerebral tissue confirmed the diagnosis of phaeohyphomycosis. He was treated with intravenous (IV) liposomal amphotericin B and voriconazole, guided by plasma and cerebrospinal fluid (CSF) level monitoring at drug initiation. At the 1 year follow-up, the patient demonstrated near complete neurological and radiological recovery. [ABSTRACT FROM AUTHOR]