I am a 22 year old with a fairly large tumor on my left ovary. During my last pregnacy my ob wanted to remove my tumor after my fifth month. Come my sixth month he decided to leave it. He said it will just disappear. It first was noticed when I was 20 and in the emergency room for a miscarriage. I was told then that it was most likely a demoid tumor that needed to be removed. I have been hearing a lot about ovarian cancer and it has me worried. I do experience frequent lower back pain, abdominal tenderness and bloating. Should I insist on a biopsy seeing how it is in fact still there?