Huge belly, suspect adenomyosis, doc says vaginal surgery?

Hi All-
I read through the fibroid-huge-belly thread just now. My "suspected" diagnosis is adenomyosis, tho' ultrasound showed a few small fibroids too. I've read through the adenomyosis pages and everything fits. But, I swear that the huge fibroid stories sound like me, too. Has anyone heard of a huge fibroid not being caught on an ultrasound?

I look 9 months pregnant and weigh 50 lbs more than I did when I was at full term. I 've been sick for 9 years now. You can look back at family pictures and see exactly when I got sick and my belly started to grow. Been on daily pain meds for 7 years. I've gained about 80 - 90 lbs since I got sick. I've had a fibromyalgia diagnosis for 7 years now, but most of my pain has always been in my abdomin, hips, lower back and legs. Belly has been growing rapidly in the last 3 months. Had to buy new pants today in a size 22. Also, I've had terrible leg swelling (pitting edema) for two years.

Haven't had insurance for many years. Just got medicaid a few months ago (what a wonderful program! It's a godsend!), so I started trying to track down this GYN problem.

I had an ultrasound about 4 weeks ago w/ a very incomplete report--didn't even have the uterus measurements! While doing the test, the tech asked me if anyone had ever told me that my uterus was folded over on itself--it was tipped backwards severely, but also folded. Also, she could hardly find the left ovary because it was hidden so far behid the uterus.

So I go to see a new GYN two weeks ago, and the Ultrasound report only says slight thickening of the uterus and diagnosis is adenomyosis. Nothing about uterus being folded, having ahidden ovary, etc. So doc asked for an addendum to the report. She called me on the phone Friday w/ new report that the uterus is about 5cm x 8cm x 10cm, and she should be able to operate vaginally. I've got a pre-op appt along with an in-office biopsy this week, and hysterectomy scheduled for Oct. 29th. (Doc just moved here from Ohio, so she doesn't have a full book of patients here. She is part of a large all-female OBGYN group.)

So, here's my big question. I'm so very convinced that there is something VERY LARGE in my belly, whether it's a huge uterus or a large fibroid I don't know. . .Is there anyway that something like that wouldn't show up on an ultrasound? What if the doc starts operating vaginally and it turns out to be too big? Would she just turn around and start on an abdominal surgery? Has anyone had something like this happen?

Thanks!