I don't know where you are located, but maybe there is someone you can find here for a second opinion or consultation: http://www.acvim.org/websites/acvim/index.php?p=2
My vets are always very good about immediately referring out when they aren't sure what is going on. In fact, the last time, my vet even went looking for the best internal med guy who would be very balanced in his approach, it was great when the name she turned up was the vet I had previously used. Anyway, some vets get very offended, some will want to talk and work with the other vet. However it works out, never hurts to get more information or opinions to evaluate.