I found a lump under the skin of my rabbit's stomach about three months ago (close to his right hind leg), I can move it freely, it is pretty hard to the touch and is the size of a grape. I went to the vet and she said I should check it regularly to see if it increased in size (it didn't). The problem is that today I was checking him and I noticed another lump right next to the other one, about half the size. Is it's possible it is cancer even if it didn't increase in size (at least not noticiably) after three months? Have anyone been through the same? He seems to be acting just fine.
He's a 9 years old rabbit and male.