Kidmayb07:
Your concerns about the tumor being or becoming malignant are fairly normal but basically unfounded. As Steve pointed out, the stats prove that the chances of an Acoustic Neuroma tumor metastasizing are infinitesimal. Yes, that could happen, just as you may be hit by a runaway tractor-trailer truck the next time you drive on the interstate, but the chances of either event actually happening are extremely small. Its your choice, but I wouldn't waste my time worrying about this. Your mom's concerns about hearing loss and facial complications following surgery are, frankly, more valid, although, again, these complications are not a given with surgery and quite often, some degree of hearing and facial mobility return in time. There are simply no guarantees with this condition but to lie awake worrying about your mom's AN becoming malignant is not really helpful to you or your mom, considering the very, very small chance of that ever occurring. Please try to relax a bit.
Jim