Thank's for the answer! I saw my neurologist in MGH (Massachusetts General Hospital) a week ago and since I don't have any disturbing symptoms (double vision, dizziness, numbness of the limbs etc.), it's OK for me to just wait and go for a follow-up MRI in six months. He mentioned that they rarely treat it surgically because it's invasive and "dangerous". If the cyst is still growing, he mentioned the draining procedure. Are you a med student or just 'generally interested' of the topic?