Casey turned 8 on June 23, 2006 and since it was so hot we did not go to the park like we normally do. Two days later, I went down to get Casey from his room and let he and Riley out to go potty, when he came inside, I noticed a bump on his hind leg. This bump was about the size of a dime in diameter and felt like a marble under his skin. Since it was Sunday, we thought we would monitor it and call the vet on Monday (when they opened up). On Monday, I took Casey to the vet and they told us he had a ?mast cell tumor?. We took him home and watched him until June 30 when we took the pictures here before and after his surgery. One day later, everything seems to be going great and aside from his leg obviously being tender and of course, as with any wound a dog receives, he wants to lick it.