J Korean Neurosurg Soc.  2015 Apr;57(4):292-294. 10.3340/jkns.2015.57.4.292.

Vestibular Schwannoma Atypically Invading Temporal Bone

• Park SJ
• Yang NR
• Seo EK

• KMID: 1956429
• DOI: http://doi.org/10.3340/jkns.2015.57.4.292

Abstract

Vestibular schwannoma (VS) usually present the widening of internal auditory canal (IAC), and these bony changes are typically limited to IAC, not extend to temporal bone. Temporal bone invasion by VS is extremely rare. We report 51-year-old man who revealed temporal bone destruction beyond IAC by unilateral VS. The bony destruction extended anteriorly to the carotid canal and inferiorly to the jugular foramen. On histopathologic examination, the tumor showed typical benign schwannoma and did not show any unusual vascularity or malignant feature. Facial nerve was severely compressed and distorted by tumor, which unevenly eroded temporal bone in surgical field. Vestibular schwannoma with atypical invasion of temporal bone can be successfully treated with combined translabyrinthine and lateral suboccipiral approach without facial nerve dysfunction. Early detection and careful dissection of facial nerve with intraoperative monitoring should be considered during operation due to severe adhesion and distortion of facial nerve by tumor and eroded temporal bone.

Keyword

Vestibular schwannoma; Temporal bone invasion

MeSH Terms

Cytochrome P-450 CYP1A1
Facial Nerve
Humans
Middle Aged
Monitoring, Intraoperative
Neurilemmoma
Neuroma, Acoustic*
Temporal Bone*
Cytochrome P-450 CYP1A1

Figure

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  Fig. 1 A : Internal acoustic canal is eroded to disappear totally. B : Temporal bone destruction is extended to carotid canal. C : In superior part of petrous bone, there was pneumatized area with thick cortex of right side temporal area corresponded to destructed area by tumor. D : 3 dimensional CT angiography shows IAC, superior part of jugular foramen, and carotid canal is invaded and carotid artery (arrow) is exposed. IAC : internal auditory canal.

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  Fig. 2 In MRI, mass is located in temporal bone and cerebellopontine angle (A), extended to tentorium (B) and jugular foramen (C). Tumor does not invade Merkel's cave and middle fossa (B and D).

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  Fig. 3 Operative photography (A) shows severe adhesion between facial nerve and tumor mass. Pathological finding (B) reveals benign schwannoma and there is no abnormal vascularity or malignant feature.

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