Angioma of the cerebellopontine cistern simulating acoustic neurinomas.

We report a cryptic angioma associated with a cisternal hematoma confined to the cerebellopontine cistern occurring in a 29-year-old woman. The angioma was related to the acoustic nerve. The cisternal hematoma appeared to have increased in size gradually with repeated hemorrhages from the angioma. The location of the lesion, in conjunction with the gradual size increase of the cisternal hematoma, resulted in the lesion simulating acoustic neurinomas radiologically as well as neurologically.