My AN was 1.8cm when I was diagnosed. While I was researching my options, my symptoms continued to increase. Around the 9 month point I developed a very intense tremor that would start at my jaw line and travel up my cheek to my eye ONLY AFTER I sneezed. My balance had also gotten worse so we bumped my 1 year MRI up to see if anything had changed. My AN had grown to 2.4cm. The neurosurgeon said it sounded like the trigeminal nerve was starting to be effected and I should make my mind up sooner than later as to what I wanted to do. I opted for Gamma Knife and had a 3 month wait for my treatment. One month prior to my Gamma Knife the tremors stopped and now at 8 months post Gamma Knife they have not returned. Other issues however have remained.
At 2.1cm, your AN has shown that it has continued to grow. Just my personal opinion here, but I wouldn't give it a chance to grow to big.
Cathie.