BILATERAL ACOUSTIC NEUROFIBROMAS

Bilateral acoustic neurofibromas, although not rare, are uncommon as compared with the unilateral lesions of this type and respond more satisfactorily to palliative surgical procedures. Since 1910, 152 proved cases of tumor of the eighth cranial nerve have been observed at the Mayo Clinic. The tumor was bilateral in only 2 of these cases; in both it was associated with generalized neurofibromatosis without a hereditary background. Bilateral tumor of the cerebellopontile angle was recorded first by Wishart 1 in 1822 and by Knoblauch 2 in 1843. Later it was described in more detail by Henneberg and Koch, 3 in 1902. In 1912 Henschen 4 described 136 cases of unilateral and 19 cases of bilateral tumor of the cerebellopontile angle. In 1915 he was able to add 109 additional cases of unilateral tumor and 5 cases of bilateral tumor which made a total of 245 cases of unilateral acoustic tumor and 24 cases of bilateral