Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system. Although brainstem involvement is common, isolated cranial nerve palsies, mostly caused by infranuclear intramedullary lesion, is rare in MS patients.1–4

In this study, we describe an MS patient who presented with isolated abducens and facial nerve palsies due to a small facial collicular lesion, and provide an anatomical review of the lesion in this case.

A 63-year-old Japanese woman had experienced three demyelinating episodes with different spinal lesions since the age of 33 years. Brain MRI revealed some cerebral plaques, and relapsing–remitting MS was diagnosed. She consulted us after she had noted acute diplopia and left orbicularis oris muscular weakness for 3 days. Neurological examination revealed palsy of the sixth and peripheral seventh cranial nerves on the left side with no other neurological deficits. She had no history of …