Update. Duke's Vet palpated the small lump and he said it appeared to be a lipoma and told me to just observe it. He said if it got bigger we would then discuss whether or not to remove it.
What was amusing was our time in the waiting area. I sat with the boys, yes Freckles has to go wherever Duke goes, and I sat in a chair next to a table with a metal elongated tub that held a variety of magazines. Every time anyone came into the office Duke would stand and that tail would start beating against that tub, clang, clang, clang. Everyone, including the staff, enjoyed the musical interlude. I just may take Duke to try out for a spot in the percussion section of the Houston Symphony. ;D
I am taking Duke in to the Vet's today at 3:00 to have that lump checked out. A simple needle aspirate should hopefully prove it's just a fatty lipoma. I just want to make sure as this is his first. I will post an update when we get home.