I have a 3cm septated ovarian cyst. At what point/size should it be surgically removed. I have a hx of Dermoid Teratoma/partial oophrectomy.

It depends. Good evening, It appears that you already follow with GYN, so they should be able to tell you when the cyst should be removed. Many times, the cyst is monitored every 6 months to a year for interval increase in size. If the size remains stable over time, there is no need for intervention. Good luck.