Small white growth in my anus. What is it? Picture attached.

[alex_nalwing]

Med student here so don't be afraid to use medical terminologies.

Age: 23 Male, caucasian

So I've had this question for years but never had it answered . ( never went to the doctor to do a checkup). About 4 years ago, on a self examination in the mirror I discovered this whiteish growth inside my anus, that tends to protrude a bit when I strain and pull my butt cheeks apart. it's about 4-5 mm long, it feels soft and it is sensitive, not necessarily painful, it doesn't disturb me during defecation, but I can feel it going back inside after straining on the toilet. Or I can feel it get sensitive when I sit on a chair for some time. I don't think it got bigger, maybe just a bit, but as I've said, I've had this thing for years.

Is it a hemorrhoid(but why is it white?), a polyp, what is it? the closest thing I could find that resembles this is hypertrophied anal papillae.

here's a picture:

http://imgur.com/7moNStb