Bit worried about the bun - swelling/lump over his ribs?

[Montyforever]

One side of my rabbits ribcage is really swollen but solid and i mean solid!! No heat, no irritation and he's still eating/drinking and behaving as normal. He's still happy to be picked up, jump on the platform in his cage and stand up on his back legs so its not restricting him at all and doesn't seem to be painful (he was happy to carry on eating while i had a poke!) the only thing thats changed is he's getting burgess excel forage mixed in with his hay for the last week or so but to be honest i think this had started before then but has slowly been getting bigger.
Im going to take him to the vets first thing Monday, he's not in pain and is still eating and drinking but obviously if he starts to go downhill ill get an emergency appointment.

So does anyone have any ideas what it could be? He's a 5 year old dutch, always been an indoor bun although gets fresh grass cuttings and is fed on pets at home nuggets and basis hay. With the occasional fruit/Veg too.

 

[Aru]

Is he in with other Buns? Could be an abscess buns have very hards pus in them.
If it is a growing lump I would be getting the vets to do a sample and see what is going on. What size is it? Is it just over the bones of the ribs or is it along the side as well?Just trying to imagine it....

If hes still eating and drinking and pooping normally plus not having any problems breathing and is happy and as active as usual I would wait for a normal appointment in the vets.

 

[Montyforever]

Nope he's on his own - always has been. But the cat does lie next to his cage/run alot so i guess he could pick something up through her possibly? It pretty much covers his ribcage and slightly further down, side and underneath .. Today when he was standing up you can see it jutting out at the side. I've tried to get a picture but you can't see much because of his fluff! I've had a good feel and i can't find any cuts or broken skin around that area. He gets a good groom at least once a week so i would have noticed if he cut himself, id say he's lost a fair bit of weight over the last week too. I dont have a good feeling about it although he's still happy now, the speed its grown is scary! I've rung the vets, he has an appointment Monday but they said to bring him in any time over the weekend if he goes downhill. They said over the phone that it sounds like a growth of some sort. My poor little fella!

 

[Montyforever]

Took him to the vets yesterday, not the best news its ether his liver/kidneys swelling or a tumor of some sort. Vet said to take him home as he's still happy/eating etc but if he starts going downhill to pts
Still, considering i bought him from pets at home and was told he probably wouldn't survive more than a few weeks he's done well bless him! He's just turned 5 and is a dutch that's the size of a dwarf, hes not put together right!