[Selective impairment and a unique recovery of bilateral horizontal gaze and facial palsy in a discrete pontine lesion: a case report].

A 77-year-old woman with bilateral horizontal gaze palsy, right hemifacial weakness and incomplete quadriplegia was transferred to our hospital. Brain magnetic resonance imaging on the first day revealed a slit-like signal deficit of the basilar artery and an abnormal signal area at the dorsal midline portion of the lower pons. Quadriplegia fluctuated in several days after admission, then disappeared finally. In spite of the recovery of quadriplegia, bilateral facial weakness appeared on Day 14 after the onset. Concerning the impairment of extraocular movements, bilateral adduction restored gradually followed by improvement of the right abduction. The clinical course suggested the involvement of bilateral medial longitudinal fasciculus (MLF) and abducens nuclei (or fibers) as the etiology of gaze palsy. Although bilateral MLF sign recovered within 3 weeks, and the abductor palsy of both eyes was persisted in mild degree. As imaging analysis did not always show the causative lesion, which correlated with the rapidly alternating signs in the patient, and careful neurological observation was therefore useful in the management of patients with brainstem dysfunction.