Very disappointing news Billy Don't give up hope though but just take a look at this CV247
I hope the vet is wrong but if there is a possibility of a tumour it is worth trying but you have to convince your vet that it is worth trying!
If you look at 'Bramble's Story' that is about a little dog I had many years ago and that is how I first got involved with the treatment.
Our little Beagle, Jan is on it now and has been for about 2 months and she is doing well. She was diagnosed with Lymphoma last December and went on a course of chemo' but although she was ok for a while after 12 weeks she started to have unpleasant side effects.
Our vet had been trying to get hold of CV247 for a very long time but couldn't because it wasn't licensed here until January this year but he got stocks of it as soon as he could and is now using it on a few of his patients.
If you read the link there is advice on the diet which if you can get them to eat it is the best support for the therapy but other than that a low protein/fat diet and organic. Jan has all the veggies and is on Burns Organic which seems to suit her.
Just a suggestion anyway.