I have a large pelvic mass, and a follow up CT scan indicates a "mucinous cystadenoma" on one ovary. I understand this is probably a benign condition. My CA125 is 23. My PCP referred me to a Gyn Oncologist; I asked the GYN Onc for an ultrasound in addition to the CT scan to make sure nothing is wrong with my other ovary. dr said the ultrasound is not necessary since I had the CT scan, and is 90% sure the cyst I have is benign, and I have no fluid in the abdomen, which is also good. Dr also told me that if it is malignant, I will require a total hysterectomy and staging. Is there anyway I can find out before surgery if the cyst is in fact benign? I want to avoid a total hysterectomy but have agreed to have one ovary removed with the mucinous cyst. I'm kind of nervous because the consent form also includes "possible TAH-BSO/possible staging." Am I worrying for nothing? I told the dr not to perform a total hysterectomy if I don't have cancer. I have no history of breast or ovarian cancer in my family, and have never had children. I'm in my early 40s and still have regular periods with no problems, and still hope to have a baby in the near future. All of my research indicates I should also have an ultrasound, but I am unable to find anything that states an ultrasound is not necessary if I've already had the CT scan. Is the ultrasound more reliable than a CT scan? Thanks in advance for any guidance you can provide.