There is a avidly enhancing extra-axial mass lesion within the right cerebello-pontine angle. On current imaging, the mass demonstrates isointense signal to adjacent cerebellum on T1-weighted imaging and low signal on FIESTA and B0 sequences. The lesion appears to be closely applied to the posterior margin of the right internal auditory canal with a thin rind of enhancing tissue extending 3mm along the dorsal wall of the right internal auditory canal.
The cisternal segment of the right CN7/8 complex is indistinguishable from the tumour, however, the intra-canalicular segments of the nerves appear to be separate from the tumour.
The tumour causes mass effect on the adjacent right cerebellar hemisphere and right brachium pontis with mildly increased FLAIR signal within the right middle cerebellar peduncle. There are no remote intra- or extra-axial mass lesions, acute haemorrhages or collections.
No acute infarcts.
The left cerebello-pontine angle and left middle and inner ear structures image normally.
Conclusion: Based on MRI features, the differential for the right cerebello-pontine angle mass lesion continues to include both meningioma and vestibular schwannoma - vestibular schwannomas are more common and remain the more likely differential.