I sense hesitation, if you have questions, ask. If the answer is not what you'd like go elsewhere. Do not sit on cancer or its possibility of starting. If a Dr. is recommending this because there is something in cyst behavior that is abnormal explore that. Be careful and persistent with cancer. It does not play fair.
That said, blessings to you and let us know how things go.
Possibly nothing BUT it may become larger ... if you were advised to have it removed then I wouldn't hesitate to do so. If it did become larger, which is likely, there would be the chance of disfigurment when it was removed. If you have doubts about what was recommended then get a second opinion from another Surgeon or whatever type of Dr. you have seen. Regards ....