MedifocusHealth

The incidence of acoustic neuromas is about one per 100,000 people. According to the National Institutes of Health, an estimated 2,000 to 3,000 new cases of acoustic neuromas are diagnosed in the United States each year. Reported incidence may be rising, however, due to improved imaging technology that enables smaller tumors to be clearly visualized. Because of the slow growth rate of acoustic neuromas, a large number of cases never become clinically evident so that the actual number of cases may be much higher. Acoustic neuromas account for approximately:

• 6% of all intracranial tumors (tumors that occur in the brain)
• 30% of all brainstem tumors
• 85% of tumors in the cerebellopontine angle region

Although they can occur as early as age 7, most people with acoustic neuromas are diagnosed when they are between the ages of 30 and 60. The median age of diagnosis is 50. The incidence of acoustic neuroma is slightly higher among women (60%) than men (40%). Acoustic neuromas occur on one side (unilateral) in approximately 95% of patients unless they are associated with neurofibromatosis-2, in which case they are typically bilateral (occur on both sides).

The overwhelming majority of acoustic neuromas are due to unknown causes. These tumors typically present later in life and are almost always unilateral. Acoustic neuromas can also be associated with a genetic condition called neurofibromatosis-2 (NF-2).