[A case of giant meningioma that induced visual changes similar to those observed in amaurosis fugax in an early stage of disease].

The patient was a 47-year-old female. A giant meningioma was detected in the right middle cranial fossa by exploration for the cause of right-sided transient monoocular blindness of a 1-2 minute duration accompanied by headache. The headache was localized on the right side, occurred more frequently early in the morning, and continued for several hours. No neurological abnormality was noted except for right-side dominant bilateral choked disc and reduced vision. Both headache and transient monoocular blindness disappeared after total resection of the meningioma. A decrease in the cerebral blood flow associated with an increase in the intracranial pressure and right-sided occurrence of paroxysmal visual impairment due to choked disc were possible mechanisms of the transient monoocular blindness. Amaurosis fugax must be initially first in patients complaining of transient monoocular blindness, and exploration for carotid artery lesions is important. In the present case, however, this symptom led to detection of a giant meningioma.