Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome in a patient with neuromyelitis optica spectrum disorder and anti-aquaporin-4 antibody

This report describes, for the first time, an occurrence of wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) in a 19-year-old female with neuromyelitis optica (NMO) spectrum disorder, who had anti-aquaporin-4 (AQP4) antibody. A high signal intensity lesion on T2-weighted MRI was detected in the midbrain tegmentum adjacent to the aqueduct, and presumably involved the medial longitudinal fasciculus bilaterally at the caudal levels. Plasma exchange resolved both WEBINO syndrome and the midbrain lesion. Although WEBINO syndrome is occasionally reported in multiple sclerosis patients, diagnosis of NMO should not be excluded in patients with WEBINO syndrome, because AQP4 is expressed abundantly around the periaqueductal region.