Cerebellopontine angle mass
A quick mnemonic to remember the common entities affecting the CPA is AMEN.
Enhancing mass
- acoustic schwannoma : ≈ 80 % of CPA masses (commonest by far)
- meningioma : ≈ 10 % of CPA masses (2nd commonest)
- trigeminal schwannoma
- ependymoma
- metastasis
High T1 signal mass
- haemorrhagic acoustic schwannoma
- neurenteric cyst : usually prepontine, but fluid may be proteinaceous and high on T1
- thrombosed berry aneurysm : often will have calcified rim, and haemosiderin staining.
- white epidermoid : rare, and will restrict on DWI
- cerebellopontine angle lipoma : usually has the facial nerve and vestibulocochlear nerve coursing through it. Will saturate on fat suppressed sequences.
- ruptured intracranial dermoid : often multiple droplets, and original midline lesion can be often seen.
CSF density mass
- epidermoid cyst : ≈ 5 % of CPA masses ( 3rd commonest)
- arachnoid cyst
