Cerebellopontine angle mass
Updates to Article Attributes
Body
was changed:
Cerebellopontine angle (CPA) masses frequently occur, many of which are relatively specific for the region.
Pathology
Cerebellopontine angle masses can be divided into four groups, based on imaging characteristics:
- enhancing mass
- mass with high T1 signal on MRI
- mass with CSF intensity/density
- other masses
Alternatively, a quick mnemonic to remember the common entities affecting the cerebellopontine angle is AMEN or SAME.
Enhancing mass
- acoustic schwannoma: most common by far (~80%)
- meningioma: second mostcommon (~10%)
- trigeminal schwannoma
- facial nerve schwannoma
- ependymoma
- metastasis, e.g. breast, lung, malignant melanoma
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; restricts on DWI
- cerebellopontine angle lipoma: usually has the facial nerve and vestibulocochlear nerve coursing through it; saturates on fat suppressed sequences
- ruptured intracranial dermoid cyst: often multiple droplets with original midline lesion still often seen
CSF density mass
- epidermoid cyst: third most common (~5%)
- arachnoid cyst
Other masses
Many other masses can present at or around the cerebellopontine angle. They include:
- primary melanocytic neoplasm
- neurosarcoidosis
- cholesterol granuloma
- paraganglioma
- petrous apicitis
- chondrosarcoma
- chordoma
- endolymphatic sac tumour
- pituitary adenoma
- brainstem glioma
- choroid plexus papilloma
- lymphoma
- haemangioblastoma
- ependymoma
- medulloblastoma
- dysembryoplastic neuroepithelial tumour
- ganglioglioma (rare 3)
-<a href="/articles/white-epidermoid-cyst">white epidermoid</a>: rare; restricts on DWI</li>- +<a href="/articles/white-epidermoid-cyst">white epidermoid</a>: rare; restricts on <a title="DWI" href="/articles/diffusion-weighted-imaging-1">DWI</a>
- +</li>
-<li>ruptured <a href="/articles/intracranial-dermoid">intracranial dermoid</a>: often multiple droplets with original midline lesion still often seen</li>- +<li>ruptured <a title="Intracranial dermoid cyst" href="/articles/intracranial-dermoid-cyst-1">intracranial dermoid cyst</a>: often multiple droplets with original midline lesion still often seen</li>
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