cerebellopontine angle mass

Schwannom am Kleinhirnbrückenwinkel rechts (links im Bild) in der MRT T1KM axial.

Schwannom am

Kleinhirnbrückenwinkel rechts (links im Bild) in der MRT T1KM axial.

A rare cause of infant facial paralysis: atypical teratoid rhabdoid tumour located in the cerebellopontine angle. a–d On the brain MRI, a dural-based, extra-axial mass lesion was observed on the left CPA, 4 × 3 cm in size, with heterogenous contrast after the application of IV contrast dye, which was heterogenous-hypointense on T1W and FLAIR sequences, heterogenous hyperintense on T2W, the mass appears to enter the cavernous sinus via Meckle’s cave. Time there is concomitant calcification, bleeding and oedema of the surrounding

A rare cause

of infant facial paralysis: atypical teratoid rhabdoid tumour located in the cerebellopontine angle. a–d On the brain MRI, a dural-based, extra-axial mass lesion was observed on the left CPA, 4 × 3 cm in size, with heterogenous contrast after the application of IV contrast dye, which was heterogenous-hypointense on T1W and FLAIR sequences, heterogenous hyperintense on T2W, the mass appears to enter the cavernous sinus via Meckle’s cave. Time there is concomitant calcification, bleeding and oedema of the surrounding

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Cerebellopontine angle (CPA) masses are relatively common. Although a diverse range of pathologies may be seen in this region, the most common by far is a vestibular schwannoma.

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

vestibular 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

hemorrhagic vestibular schwannoma
neurenteric cyst: usually prepontine, but fluid may be proteinaceous and high on T1
thrombosed berry aneurysm: often will have a calcified rim and hemosiderin 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