Does this follow-up MRI (6 months later) help?
Residual left cerebellar hemispheric atrophy following previous inflammatory insult, thus confirming cerebellitis, and excluding Lhermitte-Duclos disease.
There has been resolution of the previous abnormal T2 bright signal in the left cerebellar hemisphere. Residual T2 brightness seen peripherally does appear to be due to volume loss with increased extra-axial CSF. The deep left cerebellum, vermis and right cerebellar hemisphere show normal appearances.
The supratentorial structures are normal. The third and lateral ventricles have reduced in size from before in keeping with improvement of a degree of hydrocephalus that was present with the initial cerebellar abnormality.