Glioblastoma multiforme at internal auditory canal

Area of Science:

• Neuro-oncology
• Neurosurgery
• Pathology

Background:

• Glioblastoma (GBM) is the most common primary adult brain tumor, typically found supratentorially.
• Extra-axial glioblastomas in the infratentorial region, particularly the internal auditory canal (IAC), are exceptionally rare.
• Only three prior cases of IAC glioblastoma have been documented in medical literature.

Observation:

• A 65-year-old male presented with symptoms including headache, vertigo, and progressive right-sided hearing loss over five months.
• Preoperative magnetic resonance imaging (MRI) suggested a vestibular schwannoma due to the tumor's location and presentation.
• The patient underwent a near-total resection of the tumor.

Findings:

• Histopathological analysis confirmed the tumor as glioblastoma multiforme, not vestibular schwannoma.
• This represents the fourth reported case of an extra-axial glioblastoma originating in the IAC.
• The tumor's location and presentation mimicked a vestibular schwannoma on initial imaging.

Implications:

• This case underscores the necessity of including glioblastoma in the differential diagnosis for tumors in the cerebellopontine angle (CPA) and IAC.
• Despite its rarity, glioblastoma should be considered in the evaluation of IAC masses, even when they present atypically.
• Accurate preoperative diagnosis is crucial for appropriate surgical planning and patient management of rare brain tumors.