Bad news I'm afraid
Paul agreed with the previous vet about our options, so I took a chance on her and put her in for surgery. Best case scenario was that it was a load of dead flesh/tissue and/or some rotting food in there causing abcess and inflamation, and they would then just scrape all the gunk out.
Just had a call from them to say it wasn't so simple. They said it looked like some sort of hard tumour, and after looking at the cell scrapings under microscope, they reckoned it was a lymphoma. She was in a lot of pain without the metacam, and it was probably just going to get worse as it grew. So at 11.55 am, on Thursday 22 April 2010, I gave them permission not to wake her up.
She was far too young to go, but I know I tried for her. This is the first time in over 3 years that I haven't had a hamster to come home to.