I have not seen anything on AN's with a cyst, so cant comment. I see you started another thread, so maybe you will get responses.
The good thing is that you can wait; that gives you time to do more research. I am not sure about experience of docs at UW, but encourage you to send your MRI to Dr. Chang at Stanford, and the docs at UPMC and NYU I mentioned. They will review it at no cost to you. This is important as it seems you have only consulted w/surgeons; they do surgery, so in my experience, that's what they will advocate for.
When I was doing my research, I spoke w/someone on the WTT list who highly recommended docs at Swedish, which may be close to you. I posted info below, but I did not check them out.Here's contact info for Swedish if you want to check them out as well. They offer both Gamma and CyberKnife.
Swedish NeuroScience Specialists
550 17th Ave. Suite 500
Seattle, WA 98122
You may also want to Google Sandra Vermeulen, Swedish. She is the one who did my treatment. A truly amazing woman.
Good luck and feel free to PM me anytime.