Mysterious pelvic mass

I would really like to hear from anyone with a similar experience ...  
In August a routine ultrasound found a pelvic mass in my right side, its about 10cm by 8cm.  I am 37, no children, and have had no symptoms, apart from PCOS and a delicate digestive system that has plagued me for years but which I manage with sensible eating.  I was shocked to think I had this mass lurking!  
According to the ultrasound report, the mass has some vascularity, the contents are not mobile and it is next to but separate to the ovary. There was no fluid in the Pouch of Douglas. The final report states that it could be bowel related.
I'd had a similar ultrasound about 4 and a half years ago that didn't detect any abnormalities but I don't think the technician was as thorough as the technician for the August scan.
I was then sent (very quickly, I might add) for a CT scan which reports that it could be a cystadenoma and it doesn't appear to be related to the bowel. There are no other abnormalities.  
Next was an appointment with gyno-oncologist who examined me, took a history and some blood tests (I presume for tumour markers and cancer antigens.)  The bloods were fine and the thinking was it is most likely congenital and non malignant, possibly a fibroid.
I am having the mass removed in a few weeks but I am anxious that it could be something serious.  My biggest concern, given my dodgy digestive system, is that it could be bowel related.
Its a bit difficult to find family or friends who've had a similar experience, that's why I've posted here.  I hope someone might have a similar experience to share.

[MarieMichele]

A gyn/onc is one of the best specialists you can be seeing right now.  Clear blood tests are a very good sign.  It sounds like a benign cyst that just got too big (as many do) and it could be causing your digestive issues.  Mine did.  All is normal again now that I am cyst free.