Large Ovarian Cyst

Hi

I don't know a lot about my cyst, I see an ob/gyn tomorrow (have been waiting 2 days so far) The report from the ultrasound says that it's a 'large septate cystic lesion which is arising from the left ovary. The cyst extends to 3 - 4 cm above the umbilicus.' (I am approx 5'7 and weigh 60kgs if that helps at all) My GP said that the cyst is about the size of a 22 week pregnancy. What I would most like to know (and have been thinking about for the past 2 days) is what exactly is a 'septate cystic lesion' The GP didn't tell me, as I didn't ask (I was in shock from the size of this) Also, is this type of cyst likely to be cancerous or likely to rupture (which is my biggest fear at present) The only history that I know of in my family of cancer is my mother who passed away from a brain tumour, with lung cancer and adrenal cancer. Any information at all that you could give me on this would be greatly appreciated. Thank you