Snapshot A 44-year-old man presents to his primary care physician for worsening hearing loss. His hearing loss is most severe in his right ear. He has noticed decreased facial sensation on the right side of the face. Physical examination is notable for a sensorineural hearing loss affecting the right ear and decreased sensation to pin-prick in the right face. An MRI brain demonstrates an enlarged mass in the internal acoustic meatus, extending to the cerebellopontine angle. Introduction Overview a Schwann cell-derived tumor arising from the 8th cranial nerve typically the vestibular portion usually unilateral (~90% of cases) Epidemiology Demographics median age is ~50 years etiology Associated conditions neurofibromatosis type 2 characteristically presents as bilateral acoustina neuromas secondary to a mutation in merlin in chromosome 22 Presentation Symptoms/physical exam cochlear nerve involvement sensorineural hearing loss tinnitus vestibular nerve involvement unsteady gait can have other cranial nerve involvement facial and trigeminal nerve involvement facial nerve facial paresis taste disturbaces trigeminal nerve facial paresthesia and pain Imaging MRI brain with gadolinium indication imaging study of choice fundings enhancing lesion in the internal auditory canal that may extend into the cerebellopontine angle Studies Audiometry indication best initial screening laboratory test Differential Neurofibromatosis type 2 differentiating factors associated with bilateral acoustic neuromas, cataracts, meningiomas, and ependymomas Meningioma differenting factors tumor involving the meninges only Treatment Medical radiation therapy indication small tumors or patients who are not surgical candidates options sterotactic radiosurgery sterotactic radiotherapy Surgical microsurgical tumor removal indication large tumors or rapidly growing tumors Complications Hearing loss Brainstem compression