I thought I would write and finish my inquiry for the benefit of people that Google and find this thread in search for answers with their own dog.
First, I had to put down Franky. Anyhow, I had to put Franky to sleep. It turns out it was Osteosarcoma.
As you can read on my original posting was that he was limping, originating from one shoulder.
To the bitter end Vets were not sure what it was, only that was Cancer of some type and aspirations did not show much because it was happening from within/inside the bone. I thought Franky injured himself running, Doctor thought it was a sprain, muscle pull or even a combination of that with arthritis. Unfortunately, after 6-7 weeks a bump formed around the shoulder, while the muscles shrank. Aspirations in the area were not conclusive as the cancer was originating inside the bone. Also, the leg was getting swollen with fluid towards the end. It took us a few weeks to be able to see a doggy oncologist, but looking back, it would not have made a difference at all. We just did not know we were giving him palliative care when we were trying to nurse what we hoped was just an injury.
Anyhow, my best advise: when in doubt, get 2 or 3 vet opinions, but ALWAYS revert back to your breeder if possible. We contacted the breeder late, but she confirmed it was cancer immediately when we described the symptoms. She said Osteosarcoma just like that ran on her bloodlines. "Cancer...i have seen it before many times in our dogs".
So my suggestion is to always consult your breeder despite the years that had gone by.
Franky did not suffer much (I hope), he was always well tendered with attention and pain meds; he actually looked perky and happy. On the very day he stopped eating, he crossed the rainbow bridge. He was put down not a day too soon or too late, but i would have liked to have known that I was already giving palliative care during the weeks where we felt in "limbo" waiting to see if he would get better.
Franky was a great ambassador for the Dobbie kind, so much so, that Franky II joined us for Christmas 5 months after Franky I left us.. Its a pain having a puppy, but after missing Frank I so much, I actually like getting up 3-4 times per night to tend to junior.
All the best, see you around the forum. I hope this advise helps the next Dobe owners in my previous situation.