"Ophthalmoplegic migraine" with reversible MRI enhancement of the cisternal sixth cranial nerve

A 45-year-old woman reported multiple episodes of reversible left eye pain and diplopia stretching over 12 years. Ophthalmic examinations had repeatedly disclosed a left sixth cranial nerve palsy. Postcontrast brain MRI performed 3 weeks after clinical onset of the most recent episode demonstrated enhancement of the cisternal segment of the left sixth cranial nerve. Five months later, when symptoms and signs had largely abated, postcontrast brain MRI was normal. The clinical diagnosis satisfies the criteria for "ophthalmoplegic migraine." Although reversible cisternal enhancement of the third cranial nerve has been often described in this condition, this is the first report of cisternal enhancement of the sixth cranial nerve.