A glioblastoma mimic: successful multimodal treatment of a rare dual fungal brain abscess in an immunocompetent patient. Illustrative case.

BACKGROUND: Cerebral phaeohyphomycosis is a rare but often fatal CNS infection caused by dematiaceous fungi. Although most invasive fungal infections affect immunocompromised patients, this entity disproportionately affects immunocompetent individuals. No standardized treatment exists, and mortality frequently exceeds 70%, even with aggressive therapy. OBSERVATIONS: A previously healthy 64-year-old woman presented with progressive left-sided weakness and a parietal lesion with a presumed radiological diagnosis of high-grade glioma. She underwent three craniotomies due to rapid recurrence, and histopathological analysis and fungal culture ultimately revealed co-infection by Cladophialophora bantiana and Curvularia hawaiiensis-a combination not previously reported in an immunocompetent host. Treatment included complete abscess excision, intrathecal and systemic liposomal amphotericin B, voriconazole, and flucytosine. At the 18-month follow-up, the patient remained clinically stable on suppressive therapy with no radiological recurrence. LESSONS: This case underscores the importance of considering fungal infections in rapidly recurring cerebral lesions, particularly when postoperative evolution deviates from expected patterns. Early recognition, prompt histological and microbiological diagnosis, repeated radical surgical debridement, and prolonged multimodal antifungal therapy were crucial to this patient's survival. https://thejns.org/doi/10.3171/CASE26529.