Neuro-ophthalmic, radiographic, and pathologic manifestations of adult-onset Alexander disease

A 61-year-old woman had a 3-year history of imbalance. Eye movement studies revealed square-wave jerks, gaze paretic nystagmus, rebound nystagmus, imp aired smooth pursuit, impaired optokinetic nystagmus, and abnormal fixation suppression of vestibular nystagmus. A brain magnetic resonance imaging st udy showed extensive areas of increased signal from the middle cerebellar p eduncles and dentate nuclei, which enhanced with gadolinium. Histopathologi cal analysis of a needle biopsy specimen of the left cerebellar peduncle re vealed diffuse gliosis in the presence of symmetrically distributed areas o f demyelination. There were associated Rosenthal fibers. Clinicopathologic correlation supported a diagnosis of Alexander disease. An adult patient wi th a history of progressive imbalance, ocular motility abnormalities consis tent with cerebellar and/or brainstem dysfunction, and diffuse, symmetric h yperintense magnetic resonance imaging signals in brainstem and cerebellar white matter should suggest a diagnosis of adult-onset Alexander disease.