MRI reveals diffuse swelling and enlargement of left cerebellar hemisphere, which appears hypointense in T1W, hyperintense in T2W and FLAIR sequences. preserved striations. It shows restricted diffusion in DW/ADC. It causes mass effect on ipsilateral cerebellar peduncles and vermis, causing obliteration of foramen magnum, the fourth ventricle and effacement of superior cerebellar cistern, compression on the brain stem and mild supratentorial hydrocephalus.