I have to agree with specialmom, sounds kinda like a hemorrhoid possibly.
I go to a midwife practice and they are awesome- they have caught several things that doctors didn't, so I don't doubt that they can diagnosis something like this- but, not all midwives are going to be that good, and if you aren't getting answers from them that sound right to you- totally feel free to go and get a second opinion from another doctor. It's your health and you are allowed to get a second opinion on it!
Are you sure it's not a hemorrhoid? I had some things around that area when pregnant that were like Wowie, not human looking. One was white, rest were various shades of red and they were hemorrhoids. Pressure from pregnancy causes it. But that's just a possible answer and you say this is protruding from your vagina? Forget the midwife (they are absolutely NOT educated like doctors)--- see the ob/gyn that you go to and get this looked at. good luck and come back and let me know!