Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 8-08: Diseases of the Central Auditory & Vestibular Systems + Key Features Download Section PDF Listen +++ ++ Eighth nerve schwannomas are among the most common of intracranial tumors The lesions arise within the internal auditory canal and gradually grow to involve the cerebellopontine angle, eventually compressing the pons and resulting in hydrocephalus Most are unilateral About 5% are associated with hereditary syndrome, neurofibromatosis type 2 Any individual with a unilateral or asymmetric sensorineural hearing loss should be evaluated for an intracranial mass lesion Other lesions of the cerebellopontine angle, such as meningioma and epidermoids, may have similar audiovestibular manifestations + Clinical Findings Download Section PDF Listen +++ ++ Typical auditory symptoms are unilateral hearing loss with deterioration of speech discrimination exceeding that predicted by the degree of pure-tone loss Nonclassic presentations, such as sudden unilateral hearing loss, are fairly common Vestibular dysfunction more often takes the form of continuous dysequilibrium than episodic vertigo + Diagnosis Download Section PDF Listen +++ ++ Diagnosis is made by enhanced MRI + Treatment Download Section PDF Listen +++ ++ Depends on such factors as patient age, underlying health, and size of the tumor Consists of Observation Microsurgical excision Stereotactic radiotherapy Bevacizumab (vascular endothelial growth factor blocker) has shown promise in treating neurofibromatosis type 2