rat tumor or abcess?

Question
my female rat is only five months old and I have been to the vets twice with her she had a lump just on the side of her neck although the lump seems to have got lower now. The vet firstly said it looked like an abcess and gave her antibiotics but when they didnt clear it up said it could be a tumor. The problem is apart from the 270 pound it will cost to remove it, which I don't mind paying she is in no pain so would feel guilty if she didn't come through surgery. The lump now has black on it and greeny yellow bits coming through the skin yet she is still oblivious to it. what do you think?

Answer
Is the lump squishy, hard, semi-hard? If its soft or semi-hard, that doesn't sound like a tumor to me, that sounds like an abscess -- but did the vet even drain it, or try to aspirate it? That's what they should have done with an abscess, and then prescribed antibiotics. Antibiotics alone don't just solve the problem. Tumors are usually painless when they're just beginning to grow (not always true, but mostly I find) and abscesses only tend to get really painful when near bursting. What you can do to test my abscess theory is to hot-pack the lump several times (as often as she'll let you - though good luck, most rats hate it) and see if it comes to a head. Should only take a few times of soaking it. If it does come to a head, it'll be gross, I warn you now.

Otherwise, you may want to see about finding a vet who will give you a second opinion.