My gelding has had this since I got him. In the summer, I think its from kicking at flies and he hits his other inside hind. I have been using mtg and it does kind of peel off bits at a time. Its a hard place to photograph well due to the location on the inside. I'd like to get rid of this thing before next summer. He did have some on the other inside hind but its gone away - so I don't think it was proudflesh. Any thoughts?
Some horses will get warts. The virus is in the soil, they last about two years and then disappear much like with humans. If you are really worried about it I would call the vet. They could probably cryo freeze it or remove it surgically.