[Persistent lateral gaze palsy and abducens nerve palsy due to pontine infarction]

A 76-year-old hypertensive man noticed sudden dizziness and diplopia. On examination, right-sided gaze deviation was present, but the remainder of the neurological examination was normal. Five days later, MRI revealed a small lesion in the left paramedian pontine tegmentum, which was consistent with pontine infarction. The conjugate deviation disappeared about two weeks after the onset, but a left lateral gaze and abducens nerve palsy have persisted at ten months after the infarct. MRI findings are unchanged. The site of infarction is presumed to be located in the caudal portion of paramedian reticular formation and the abducens nerve fascicle. Persistent lateral gaze palsy is rare in pontine infarction, and this case is important in illustrating the anatomical location of paramedian pontine reticular formation.