Thanks for answering.
Could you please see below report of MRI and suggest me about the size of arachnoid cyst. How critical is it?
Supratentorial:
A large CSF signal intensity lesion is seen in right temporal to grontoparietal region measuring 100.4 (CC) * 88.35 (AP) * 46(W)mm widening the right sylvian fissure and causing scalloping of calvaria. No restricted diffusion or post contrast enhancement is seen. Mass effect is seen evidenced by displaced right lateral ventricle and mid line shift to left 8.8mm. No abnormal parenchymal or leptomeningeal enhancement is seen.
If the doctor's did not already tell you, a arachoid cyst is "sack" filled with cerebral fluid. The same fluid that is already surrounding your brain. The growth rate depends on allot of different factors so it is hard to determine. Normally they are not dangerous but as with everything some can be. Depending on the size of the cyst and if it is causing you serious problems I would feel safe waiting 7 months. If I had to guess I would say the doctors are just going to cut it open and let your body re-absorb the fluid .
You should be fine, but this is your health we are talking about and you have to decide what is best for you.
I could be wrong but I do believe that 100.4 cc's equals about 6 tablespoons of fluid. Which would be a pretty good size cyst. The 46 mm widening of the right sylvian fissure is about 1 1/2 inches. I do not think that is to bad, a fissure to me is the gap that looks like were the brain "folds" onto it's self. Your mid-line shift of 8.8 mm is small to me, less than .4 inches.
As for how critical the cyst is I can't say for certain, that would be something only a neurologist can tell you. I still think you could wait the 7 months, but if you can get it done sooner I would. Why take the chance of something going wrong.