It's probably benign, sweet! Don't worry too much about it, but make sure you get it taken care of.
From what I can get out of it . . . they are trying to see if your cyst is benign (non-cancerous) cyst or a result of endometriosis (extra tissue accumulating outside your womb). A neoplastic process is an abmornal growth of tissue where it just keep on pregressing and getting bigger. This may or may not be cancerous. Basically, it looks like they are saying that you do not have a fluid-filled cyst (like sometimes occurs on the ovaries . . . but that they think it is tissue filled. They don't know what type of tissue cyst it is. You should get your pelvic ultrasound for a better look, an MRI would be even better. If they still can't figure it out, they may advise some sort of biopsy to take a look at the tissue. I wouldn't get too concerned yet, but definately put pressure to make sure that you get those follow-up tests as soon as you can.
Hope that helps.