My second Yorkie had that, too. I got her when she was 9 months old and she wasn't spayed yet. When I took her to a vet check, I pointed it out to the vet (it was easier to feel than it was to see). He took a "look see" the next week when she was spayed and said it was nothing but the remnants of a navel.
__________________ Life is merrier with a Yorkshire Terrier! Jezebel  & Chuy  ... RIP: Barkley  Loosie  & Sassy  |