An acoustic neuroma is a benign, usually slow-growing tumor that develops from certain nerves in the inner ear. No one knows the exact cause or causes of the tumor. As an acoustic neuroma grows, it presses against the nerves associated with hearing and balance, resulting in early symptoms such as one-sided or high-tone hearing loss, ringing in the ear, dizziness, and loss of balance. Once an accurate diagnosis is made, the doctor can describe the available treatment options.