Thanks for joining the ANA forums and posting!
First, I want to state that I'm not a physician, and there is no way that I could possibly diagnose your situation or give you any medical advice.
But, with that said, please do not become too anxious over the neurosurgeon wanting to see you. It could be that your acoustic neuroma has grown some (although they typically do not grow very fast and yours hasn't grown much in recent years). Or, it could be that your neurosurgeon is concerned about your worsening symptoms. I would certainly hope that your neurosurgeon would want to see you if he/she learned that your symptoms have become worse. That should be a concern for them, even if your tumor has not grown any at all.
You asked for reassurance, and my guess would be that your doctor is just concerned about your symptoms getting worse and wants to talk with you about what you could do for your symptoms. But again, that is a total guess on my part.
Please let us know when you find out more!
Best wishes on your journey!