Consider bringing your images to an academic center for a second opinion.
Glad to hear it! Thanks for the update.
Good for you for pushing back on removal of your ovaries!! I wish I had fled my long-time (previously respected) gyn's office when he used ovarian cancer scare tactics and rushed me into surgery. I regret it every single day and hope to save many other women from these incredibly destructive surgeries (hysterectomy and oophorectomy) that are rarely necessary. The medical literature has shown over and over again that removal of any part of our "reproductive" system (even one ovary) causes harm yet ~90% of these surgeries are still unnecessary. Of course, I'm now a skeptic on all things medical with gynecology at the top of the list.
Of course, neoplasm and tumor are scary words to many but they can be benign or malignant.
How big is the cyst? Sounds like the cyst is encapsulating the ovary hence why there's no visible ovarian tissue (not all that surprising since the ovary is the size of a walnut). But a surgeon with good cystectomy skills could probably save the ovary or most of it (if they side on patient's health versus $$$).