A vestibular schwannoma, a benign tumor on the nerves leading from the inner ear to the brain.

A vestibular schwannoma, previously called acoustic neuroma, is a benign tumor that develops on the balance and hearing nerves leading from the inner ear to the brain. These nerves twine together to form the vestibulocochlear nerve (eighth cranial nerve). The pressure on the nerve from the tumor may cause hearing loss and changes in balance.