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Cerebellopontine angle mass
NeuroMRI
A mass in the CPA cistern presenting with hearing loss, tinnitus or facial symptoms. Relationship to the internal auditory canal and signal characteristics are key.
Differential
Vestibular schwannoma
common- •Extends into and widens the internal auditory canal ("ice-cream cone")
- •Acute angle with the petrous bone
- •Avid enhancement; may be cystic; no dural tail
Meningioma
common- •Broad dural base, obtuse angle with petrous bone
- •Dural tail and hyperostosis; homogeneous enhancement
- •Rarely extends into the IAC
Epidermoid cyst
less-common- •Follows CSF on T1/T2 but restricts diffusion (bright DWI)
- •Insinuates around vessels/nerves, no enhancement
- •Incomplete FLAIR suppression
Arachnoid cyst
less-common- •Follows CSF on all sequences including DWI (no restriction)
- •Complete FLAIR suppression, no enhancement, displaces vessels
Facial nerve schwannoma
rare- •Extends along the facial nerve into the labyrinthine segment/geniculate
- •Facial nerve palsy
Metastasis / lymphoma
rare- •Leptomeningeal/multifocal enhancement
- •Known primary; cranial neuropathies
Key discriminators
- •IAC involvement (schwannoma widens; meningioma usually spares)
- •Angle with petrous bone (acute schwannoma vs obtuse meningioma)
- •Dural tail (meningioma)
- •Diffusion restriction (epidermoid) vs CSF-matching (arachnoid cyst)
- •Pattern of enhancement
Work-up / next steps
- 1.Thin-section high-resolution T2 (CISS/FIESTA) through the IAC
- 2.Post-contrast T1 and DWI for tissue characterisation
- 3.Audiometry correlation
- 4.Interval imaging or resection/radiosurgery per size and symptoms
References
- Radiopaedia: Cerebellopontine angle mass.
- Osborn AG. Osborn’s Brain, 2nd ed.
Educational clinical decision support only. This differential does not make a diagnosis, is not a medical device, and must never substitute for interpretation by a qualified radiologist correlated with the full clinical picture and prior imaging.