We report the case of a patient with pre-existing multiple sclerosis, who presented with horizontal diplopia, and a prior episode of progressive ataxia and dizziness lasting one week. While initially attributed to multiple sclerosis, subsequent imaging demonstrated a concurrent left cerebellar gangliocytoma, also known as Lhermitte-Duclos disease.
Keywords: Lhermitte-Duclos disease; Multiple Sclerosis; cerebellar gangliocytoma.