5cm mass on left ovary, doctor is contradicting himself

I posted this question on the general support forum, but would like to get an opinion from a medical professional if possible. I have been having some problems and recently ended up in the emergancy room with sever abdominal pain. An ultrasound revealed a 5cm mass on my left ovary and fluid in my abdomin (abdomen). The ER Dr. said that it was probably just my endometriosis, but to follow-up with my gyno on monday. When I went to my gyno, he seemed conserned. Said that they would have to remove the mass and do a biopsy, but he wanted to schedule and MRI to get a better look at it first. I asked him about the endo. and he said that endo doesn't show up as solid on an ultrasound and the radiologist stated that it was a solid mass. I had my MRI on Friday and my follow-up with my gyno yesterday. The gyno then tells me that it's just my endo and they usually dissolve on their own so he will schedule another ultrasound in a few months to follow-up with it? When I asked him why he no longer wanted to biopsy it he said that I was to young for ovarian cancer. What worries me the most is that he seemed like he didn't even know who I was. He has been treating my endo for the last five years, he is the one that diagnosed it and yesterday he asked if I had ever had a laparoscopy to formally diagnose endo...he's done three laps on me, all in the chart right in front of him!!! So, anyways, my question is, should I be seeking a second opinion. I really don't want to have surgery if it's not necessary, but everyone in my family has died of cancer and most of them because they waited and didn't catch it in time.

[Annekathryn Goodman, M.D.]

Hi There,
I would suggest that you get a second opinion. It can be very helpful to have a fresh set of eyes look  at your films and think with you about the best options. My personal leaning in someone with pain and a 5 cm mass is to take a look surgically with laparoscopy. Most masses and ovarian cysts are benign but that does not mean one should not check and maybe remove them if they are causing symptoms
best wishes