Schwannoma arises most frequently from:

A schwannoma (also known as acoustic neuroma, acoustic neurinoma, or acoustic neurilemoma) is a benign, usually slow-growing tumor that develops from the vestibular nerves supplying the inner ear. The tumor comes from an overproduction of Schwann cells--the cells that normally wrap around nerve fibers like onion skin to help suppo and insulate nerves. As the vestibular schwannoma grows, it presses against the hearing and balance nerves, usually causing unilateral (one-sided) or asymmetric hearing loss, tinnitus (ringing in the ear), and dizziness/loss of balance. It comprises 5-10% of all intracranial neoplasms in adults. Incidence peaks in the fifth and sixth decades and both sexes are affected equally.