[Case of multiple sclerosis with WEBINO syndrome].

We report a 50-year-old man presenting with wall-eyed bilateral internuclear opthalmoplegia (WEBINO) syndrome. He had suffered from progressive double vision and tetraparesis, and been diagnosed as secondary progressive multiple sclerosis (MS). On admission, he presented with bilateral facial nerve palsy, pseudobulber palsy, and spastic tetraparesis, predominantly on the right side. Bilateral adduction deficits were noted on horizontal gaze, together with nystagmus of abducting eyes. On primary eye position, the right eye was fixed in the midposition, while the left eye was exotropic. The right eye was deviated outward on fixation with the left eye. Vertical gaze and convergence were preserved. These ocular findings were compatible with WEBINO and considered to result from impairment of bilateral medial longitudinal fasciculus and imbalance of paramedian pontine reticular formation on both sides. T2-weighted images of MRI revealed a high signal lesion in the paramedian pontine tegmentum without enhancement. He underwent steroid pulse therapy, followed by mild improvement in adduction of both eyes. Although WEBINO tends to be observed in the acute stage of stroke, this patient suggests that demyelinative lesions of MS can cause persistent WEBINO, involving the paramedian pontine tegmentum.