Brenda,
Many hugs to you! What a way to find out! I wonder, would they tell you some day or just wait for you to have symptoms when the tumor grows too big to have any choices?!! This reminds me of my own situation when the first neurosurgeon told me, my family and everybody else that he got all the tumor out. Only 10 years later when there was no mistake that the remnants were not scar tissue but a live, growing tumor, he admitted that he did not take all of the tumor out because "one end of it was too far and very friable". Maybe I would not be alive today if got it all out, who knows. He had, however, to tell me that something is left! Needless to say, it affected my life in a big way.
I sincerely hope that your other AN is the same size, you have all the options open to you and , very importantly, preserve your hearing. Do you have any symptoms right now? MS can be easily confused with AN or two ANS. Did that prompt all the testing?
Eve