Gerbil has a sort of tumor?

[Pollux]

I noticed it a few days ago... One of my male gerbils has been walking slanted, almost like there's something heavy one one side. When I looked closer there's a big lump right between it's ear and eye is this huge pink bulge that's red and inflamed. It's got some pus around it, and the ear looks ragged and there's a bit of red matter in the corner of it's eye, almost like it spread. The eye actually can't open because the swelling is too large.
I've also noticed that this gerbil is skinny, underweight, freakishly anorexic. When I hold it, I feel every bone and every juncture and bump in it's spine, and the leg bones stick out a lot. This has nothing to do with me not feeding it or not giving it water. I feed them once a day, and the other one is perfect weight - if not a little plump. I watch them after I give them food, and the sick gerbil ignores it.
Please, if anyone knows what this could be? Should I disinfect it? Is there any hope for the gerbil? Should I separate the gerbils in case it can spread? Should I euthanize it? I'm not really going to consider surgery, because the gerbil is already 3 1/2 years old and wouldn't have much longer to live anyways. I just want to put him out of his pain.

[sqeakywheel]

you should bring him to the vet and see what he/her thinks.
like you said, he's old so maby the best thing for him would to be put to sleep.
lack of eating is usually a sign of illness.
you should get it sorted soon because he could be in pain which is un-fair on him.

[gerbildaddy]

I really feel for you . Ive just discovered a lump on the tummy of my male gerb Jerry, likely a scent gland tumour, and even though he doesnt seem bothered by it at all, I am worried sick! Our little boys cause us so much concern dont they?

I agree you should get to the vets ASAP, try to find one who has gerbil experience if you can. He sounds so poorly bless him, and he's a good age for a gerb, the vet will be able to advise you as to what to do for the best.

Thinking of you xx