hi there, it would have been good if I had known your age, but anyways hyperechoic is a term used for radiologists to denote that something is solid as is your dermoid cyst
. Dermoid cysts can be benign or harmless or it could be malignant, we can come to know that only when a histopathological exam of the cyst is done. It would be a good option to get the cyst removed and then according to the nature of the cyst to initiate treatment. You should visit your gynacologist and get her opinion as to the future course of action. An operation may be a possiblity and you should get it done. Do not neglect it and take action as per your attending doctors advise. Take care.