Abstract
Fisher syndrome (FS) is an autoimmune peripheral neuropathy that occurs in 1 person per 2 million population. The present report is of a patient with FS who presented with diplopia and discomfort of the right cheek and in whom differentiation from maxillary sinus cysts was necessary. The patient was a 43-year-old man with a history of radical surgery of the right maxillary sinus, so we suspected that his symptoms were due to postoperative maxillary sinus cysts. Although computed tomography demonstrated right maxillary sinus cysts, these cysts were not likely to be the cause of the patient's diplopia. Close neurological examination revealed external ophthalmoplegia, cerebellar ataxia, and the absence of a deep tendon reflex; on this basis, a diagnosis of FS was made. Diplopia is caused by various disorders and FS should be taken into consideration when making a differential diagnosis.
