Hello and thanks for posting on the forum,

I am sorry to hear that you are going through different investigations. The doctors will have a good idea by looking at the MRI and ultrasound but they will then be able to confirm what kind of cyst it is when it is removed and the pathologist looks at it under a microscope.  We do have some information on the website about these particular cysts and how they are treated which you can look at here

As you can see from the information mature teratomas are the most common type of ovarian germ cell tumours.  They are non cancerous (benign).  Mature teratoma is often called a dermoid cyst. 

As we are nurses and not involved in your care we can't tell you what the chances of it being an immature teratoma but it sounds like the doctors think that it is a dermoid cyst.

I hope that this has been helpful. Please get back to us if you need any more information or support.  You may find it helpful to talk things through with one of the nurses on our helpline.  The number to call is Freephone 0808 800 4040 and the lines are open from 9am till 5pm Monday to Friday.

Best Wishes,

Catherine