Glioblastoma of the cerebellopontine angle and internal auditory canal mimicking a peripheral nerve sheath tumor: case report

Abstract

Glioblastoma (GBM) of the internal auditory canal (IAC) is exceedingly rare, with only 3 prior cases reported in the literature. The authors present the fourth case of cerebellopontine angle (CPA) and IAC GBM, and the first in which the lesion mimicked a vestibular schwannoma (VS) early in its natural history. A 55-year-old man presented with tinnitus, hearing loss, and imbalance. MRI identified a left IAC/CPA lesion measuring 8 mm, most consistent with a benign VS. Over the subsequent 4 months he developed facial weakness. The tumor grew remarkably to 24 mm and surgery was recommended; the main preoperative diagnosis was malignant peripheral nerve sheath tumor (MPNST). Resection proceeded via a translabyrinthine approach with resection of cranial nerves VII and VIII, followed by facial-hypoglossal nerve anastomosis. Intraoperative frozen section suggested malignant spindle cell neoplasm, but final histopathological and molecular testing confirmed the lesion to be a GBM. The authors report the first case in which absence of any brainstem interface effectively excluded a primary parenchymal tumor, in particular GBM, from the differential diagnosis. Given the dramatic differences in treatment and prognoses between malignant glioma and MPNST, this case emphasizes the importance of surgical intervention on an aggressively growing lesion, which provides both the best probability of local control and the critical tissue diagnosis.

Cerebello-Pontine Angle Glioblastoma with Cervical Spine Metastasis: A Case Report

“…This case is noteworthy for several features, including the exceptional location in the cerebellopontine angle (with 10 reported cases), the clinical onset with rapidly progressive hearing loss and trigeminal pain, and the subsequent tumor seeding in the cervical spinal cord, inspite of the tumor control at the initial location. Among the 10 reported cases [2][3][4][5][6][7][8][9][10][11] (Table 1) seven were men and three women; three of them were very young (22-years-old or less). Six were exophytic tumors arising from the cerebellum [3,7,9] or pons [2,4,6] and three [5,10,11] arose from the eighth cranial nerve (likely from the nervous tissue of its proximal part or from neuroglial cells in the surrounding leptomeninges).…”

“…Primary infratentorial glioblastomas are uncommon in adult patients and are found in the cerebellum (1.5%) or brainstem (4.1%) [1]. The cerebellopontine angle is an exceptional location of glioblastoma, with only 10 reported cases [2][3][4][5][6][7][8][9][10][11]. Six of them were intra-axial, arising from the cerebellum [3,7,9] or pons [2,4,6], with lateral exophytic growth.…”

“…Three cases [5,10,11] were primary extra-axial glioblastomas of the cerebellopontine angle arising from the root entry zone of the eighth cranial nerve, Radiotherapy with concomitant and adjuvant temozolomide, according to the Stupp [12] protocol, was administered. Magnetic resonance studies at 3 and 6 months showed no residual tumor.…”

Glioblastoma in the Cerebellopontine Angle in a Patient with Neurofibromatosis Type I: A Case Report and Review of the Literature

“…[4][5][6][7][8][9][10][11] Only three of the described lesions involved the IAC. 3,5,12 None of the patients in the literature had syndromic or genetic predispositions that contributed to tumorigenesis.…”

“…[4][5][6][7][8][9][10][11] Internal auditory canal (IAC) involvement is rare, with very few cases reported in the literature. 3,5,12 There is no documented association between CPA glioblastomas and genetic or syndromic disorders. We present a case of a 48-year-old patient with neurofibromatosis type I (NFI) with an intra-axial GBM arising within the CPA.…”