Dog Skin Flaky Dark Spots My Dog Has A Flaky Dark Spot On His Belly?

My dog has a flaky dark spot on his belly? - dog skin flaky dark spots

Please time before answering this question will be informed, I am very worried for my dog.
During the past 3 weeks my dog has a black spot develops in its belly scales. It is not difficult, it does not bleed, and no meat. looks like a birthmark, but with the skin peeling.
What is it? I read online people connected with this type of cancer? Please let me know if there is something we need to address.

Here is a picture:

http://i283.photobucket.com/albums/kk318 ...