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MR shows extra-axial lobulated cystic space-occupying lesion in the right cerebellopontine angle cistern. It demonstrates low signal on T1WI, a high signal on T2WI, heterogeneous or dirty signal on FLAIR and high signal on diffusion-weighted imaging. There is no enhancement after contrast administration. The mass exerts significant mass effect, adjacent right cerebellar hemisphere, brainstem, and the fourth ventricle are compressed. There is also cerebellar tonsillar caudal herniation. The third and lateral ventricles mildly dilated.