Dog has a pinecone shaped growth on his paw, any clue as to what it is?

I was playing with my new American Bulldog I got and I noticed after we were skidding across the back deck that he stopped and sat down and started to lick his back paw. I had noticed a scab of some sort on his paw when I got him, but upon closer examination, it looks to be some sort of small pinecone shaped growth between his main pad and his first outside pad. It doesn't seem to bother him a lot, this is actually the first time I have seen him pay it any attention. It's about 1/4" x 1/4" and looks like a tiny pinecone. It is definately attached to his paw and it's split open and I can see the 'meat' inside it. Any ideas?