DEAR DOCTOR K: I’ve been having trouble with my hearing. My doctor thinks it might be an acoustic neuroma and is ordering tests for that. I don’t like the sound of this. Isn’t an acoustic neuroma a type of brain tumor?
DEAR READER: Yes, an acoustic neuroma is a type of brain tumor. There are really bad brain tumors and there are small, curable brain tumors. Fortunately, an acoustic neuroma usually falls into the small, curable category.
Acoustic neuromas are benign (noncancerous) growths, or tumors. Part of a nerve swells up into a little ball. These growths do not spread into other parts of the brain or body.
An acoustic neuroma grows on the cochleo-vestibular nerve (the eighth cranial nerve). This nerve allows a person to hear and is also connected to the balance center inside the ear. It carries sound and balance information from the ear to the brain. For that reason, the main symptoms of an acoustic neuroma are hearing loss and tinnitus (ringing in the ears).
There is no way to tell how fast a tumor will grow except by checking periodically with an MRI scan. Some acoustic neuromas can grow quickly, but most grow slowly, taking years to become large enough to cause symptoms. And some acoustic neuromas do not grow at all after they are diagnosed.
If no changes are found, yearly checkups are considered adequate to monitor the tumor. If the tumor does not grow, and your symptoms don’t worsen, intervention is not needed. There is a small risk that further permanent hearing loss can occur during this “watchful waiting” period.
If the tumor is growing or is pressing on the brainstem, radiation or surgery will be necessary. The brainstem is responsible for many vital functions, including breathing and heart rate. It’s dangerous not to remove or shrink the tumor.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.