Temporal bone meningioma is an extra-axial benign tumor originating from arachnoid cap cells. It may be seen in the cerebellopontine angle (CPA), at the internal acoustic canal (IAC) entrance, or rarely in the middle ear/mastoid. CPA meningioma accounts for approximately 10-15% of all CPA lesions. It is 2-3 times more common in women than men, with mean age of diagnosis 50-60. Clinically, it may present with hearing loss, tinnitus, vertigo, and facial nerve dysfunction — this clinical picture overlaps with vestibular schwannoma and imaging-based differential diagnosis is mandatory. Bone hyperostosis or en plaque appearance on CT, intense homogeneous enhancement and dural tail sign on MRI are characteristic imaging findings. Differential from vestibular schwannoma: schwannoma widens IAC, meningioma does not widen or minimally widens IAC; schwannoma no dural tail, meningioma dural tail +.
Age Range
40-70
Peak Age
55
Gender
Female predominant
Prevalence
Rare
Temporal bone meningioma develops from cap cells of arachnoid villi. In the CPA, it grows with a broad base on the dura — this appears on contrast-enhanced MRI as the 'dural tail sign'. The dural tail represents reactive dural hyperemia and/or tumoral infiltration at the tumor margin. The tumor is fibrovascular in structure and is supplied by dural arteries — this rich vascular network explains the intense homogeneous enhancement. Calcification in the form of psammoma bodies is common and appears as hyperdense foci on CT. Pressure effect on bone may create hyperostosis (reactive bone thickening) — this finding is characteristic on CT and is not seen in schwannoma. Progesterone receptor positivity explains female predominance and growth acceleration during pregnancy. IAC widening does not occur or is minimal in meningioma because the tumor does not grow into the IAC, remaining attached to the dura outside the canal — schwannoma originates from within the IAC and widens the canal. En plaque meningioma forms a flat lesion spreading along the dura and covers the bone surface.
Tapering dural enhancement at lesion margins on post-contrast T1 sequences is the most characteristic imaging finding for meningioma. The dural tail reflects peritumoral dural reactive hyperemia and/or tumoral infiltration. Not seen in other CPA lesions (schwannoma, epidermoid). However, not pathognomonic — may rarely be seen adjacent to schwannoma or metastasis.
An intensely and homogeneously enhancing extra-axial mass with broad-based dural attachment in the CPA is observed on post-contrast T1 sequences. Dural tail sign: tapering dural enhancement at lesion margins — highly characteristic of meningioma but not pathognomonic. CSF cleft is visible between tumor and brain. Enhancement intensity is more pronounced and homogeneous than schwannoma. Heterogeneous enhancement suggests higher grade or cystic degeneration.
Report Sentence
An extra-axial mass measuring ___ cm with broad-based dural attachment in the CPA is identified, demonstrating intense homogeneous enhancement with dural tail sign at lesion margins; meningioma should be the primary consideration.
Hyperostosis (reactive bone thickening) of the temporal bone adjacent to the meningioma may be seen on CT bone window reconstructions. En plaque meningioma shows flat bone thickening spreading along the dura. Psammomatous calcification within the tumor is detected in 20-25% of cases. IAC widening is absent or minimal — significant IAC widening ('ice-cream cone' appearance) is characteristic of schwannoma.
Report Sentence
Bone hyperostosis/calcification in the ___ region is identified on CT bone window reconstructions, consistent with meningioma; IAC widening is not present.
On T2-weighted sequences, meningioma generally appears iso-to-hyperintense relative to gray matter. Signal variability depends on histological subtype. CSF cleft is prominently visible as hyperintense on T2, confirming extra-axial location. Peritumoral edema is variable.
Report Sentence
An iso-to-hyperintense extra-axial mass relative to gray matter is identified on T2-weighted sequences with CSF cleft between tumor and brain.
An isointense extra-axial mass relative to gray matter is observed on T1-weighted sequences. T1 hypointense CSF cleft between tumor and brain is seen — the most reliable indicator of extra-axial location.
Report Sentence
An isointense extra-axial mass relative to gray matter is identified on T1-weighted sequences with CSF cleft between tumor and brain.
Meningioma generally shows NO diffusion restriction on DWI — ADC values are normal or elevated. This finding helps in differential diagnosis from schwannoma (DWI variable) and epidermoid cyst (DWI markedly bright). Diffusion restriction may be seen in higher-grade (atypical/malignant) meningiomas.
Report Sentence
No diffusion restriction is identified in the mass on DWI (ADC values normal), consistent with benign meningioma.
Criteria
Most common temporal bone meningioma type. Broad-based dural attachment in CPA. May sit at IAC entrance but does not widen IAC.
Distinct Features
Differential diagnosis from vestibular schwannoma is the most important clinical problem. Dural tail +, IAC widening -, calcification + (opposite in schwannoma).
Criteria
Rare. Ectopic meningioma in middle ear or mastoid. May be extension of intracranial meningioma through tegmen tympani defect or primary ectopic lesion.
Distinct Features
Conductive hearing loss. Soft tissue in middle ear + bone hyperostosis on CT. Differential from paraganglioma important.
Criteria
Flat, sheet-like meningioma spreading along the dura. Diffuse dural thickening instead of focal mass.
Distinct Features
Bone hyperostosis more prominent. Imaging shows dural thickening + bone thickening instead of focal mass.
Distinguishing Feature
Cholesterol granuloma: T1+T2 hyperintense, no enhancement, at petrous apex. Meningioma: T1 isointense, intense enhancement, dural attachment.
Distinguishing Feature
Epidermoid: no enhancement, DWI bright. Meningioma: intense enhancement, no DWI restriction.
Distinguishing Feature
SCC: aggressive bone destruction + heterogeneous enhancement. Meningioma: bone hyperostosis (not destruction) + homogeneous enhancement.
Urgency
routineManagement
surgicalBiopsy
Not NeededFollow-up
6-monthObservation is sufficient for small asymptomatic lesions (annual MRI). Surgical resection or stereotactic radiosurgery (gamma knife/CyberKnife) is performed for symptomatic or growing lesions. Recurrence-free survival at 10 years exceeds 90% for WHO grade 1 meningiomas. Facial nerve and hearing preservation is the primary goal of surgical planning. Retrosigmoid or suboccipital craniotomy approaches are used for CPA meningiomas. Transmastoid approach is preferred for middle ear meningiomas.
Observation is sufficient for small asymptomatic lesions. Surgical resection or stereotactic radiosurgery (gamma knife) is performed for symptomatic or growing lesions. Prognosis is excellent for WHO grade 1 meningiomas. Facial nerve preservation is critical for surgical planning.