I found a "bump" on Apollo's hind leg one day. It was flesh-colored, but slightly red or "irritated" looking. I called the Vet, and they said it sounded like a cyst. We took him in and they confirmed it. They gave us a cream and said if it burst, or broke, to bring him back in (danger of abscess). After about a week on the cream, it "dissolved" (for lack of a better term) and we've had no further problems.
I would call your Vet, describe the anomally, and let them advise you on what to do. It's more than likely nothing to be concerned about, but if it's something scary or serious, early treatment could be crucial. A phone call would be a very good idea.
Best of luck, and let us know what it turns out to be.