Diagnostic and management challenge of a pediatric H3K27-altered glioma masquerading as vestibular schwannoma.

Pediatric H3K27-altered glioma most frequently arises from midline cerebral parenchyma, whereas intracranial extra-axial locations are exceedingly rare. We report the case of an 8-year-old boy who presented with chronic-onset left-sided hearing impairment and peripheral facial paralysis. Radiological imaging identified an isolated cerebellopontine angle lesion distinct from surrounding structures. A vestibular schwannoma was diagnosed based on preoperative examinations. Surgical resection revealed an unusual facial nerve-infiltrating mass with distinct vascular features. Histopathological assessment yielded an unexpected diagnosis of H3K27-altered diffuse midline glioma, contrasting with initial preoperative impressions. This exceptional case illustrates diagnostic pitfalls in pediatric skull base pathologies and expands the recognized spectrum of diffuse midline gliomas.