I’m sorry to hear about your husband. I have read you can not have radiation on a tumor larger than 3 cm, however, being your husband is basically symptom free maybe he can? My husband was diagnosed with 2.5 cm acoustic neuroma with also, a cyst attached 3 1/2 years ago. He had no symptoms either other than hearing loss. We found the tumor by fluke. Dr. Sisti (NYC Columbia) was the only neurosurgeon we visited that recommended Gamma Knife over surgery. All of the other doctors said the tumor was too big for radiation and they were also concerned about the cyst attached. Thank God we chose Dr. Sisti. My husband still has no symptoms other than hearing loss and full quality of life. It has been a little bit of a rollercoaster ride because his tumor died after radiation then grew back & now dead again with no additional treatment. He has a few more small cysts grow (not tumors after radiation) but he feels great!! Living with full quality of life other than hearing loss which he had before gamma knife. I would ask Dr. Sisti, being he has no symptoms maybe he can have Gamma Knife? Good luck!