A 3.1x3.0x2.3cm cyst (simple) on my right ovary, vol 30cc endometrial thickness 12mm in secretory phase, history-11cm teratoma removed 2 yrs ago.?

Ovarian Cyst: Your concern of another ovarian teratoma is understandably quite normal, but with the report that you just mentioned here of its size and characteristics( depending on your risk factors and other contributing circumstances) i think that there is room for observation of the above cyst . You will benefit with a short term follow up and a repeat ultrasound.