My 13 year old boxer boy who has been diagnosed with diabetes incepitus has developed some large dark areas on his tummy. They seem to be scabbed over though I don't know when he got them. They are itchy because he makes his leg move like he wants to scratch them. I put cream on the spot and he now has developed another spot a few inches from the first one which is about the size of a silver dollar, the other is the size of a quarter. I am afraid that he may have cancer. Taking him to the vet tomorrow. Anyone have a similar experience?