Tumor on groin

Question
My little bun is six years old. He's been through a lot in his life and has been a trooper. The first traumatic experience was two years ago when he was bitten by a spider (adult black widow), was completely paralyzed and came back within a few hours. It took about a week to rehabilitate him, though he suffered brain trauma and has never been quite all there. Unless he runs, he hobbles around as his back legs seem weak. Peanut is still the sweetest rabbit, energetic, and will follow anyone around. He can't clean himself well past his hips, so we have to give him a half bath to help.

A few months ago, while trimming his nails, I noticed his hind legs and groin were missing a lot of fur. I checked things, but there seemed nothing wrong. Last week, I was doing the nail trim and found a lump half the size of a golf ball. At first, I though he developed a testicle (he's been fixed since he was old enough!) but it wasn't in the right spot. It's very round and can be pushed a bit. He didn't react as if in pain, but that could be due to his head not being all there. I have a vet appointment tomorrow.

My question is this: if it is something needing surgery, should it even be an option because of his current health? I don't want to make a rash decision to put him through more trauma. I trust my vet, but thought I could ask here, too. Any advice would be great. I don't want to lose my baby, but I don't' want to make things worse for him either.

Answer
Dear Keri,

Whether or not surgery will be recommended for this will depend on how good a surgical candidate your vet thinks your bunny is.  Blood work will give some clues, and might be useful.

If the lump moves with the skin, that's good.  If it's attached to underlying tissues, not so good.  But there are things this could be that are not cancer, and the most common would be an abscess.  Unfortunately, rabbit pus is very solid, and such an abscess is usually best treated as a tumor, removed whole with the capsule intact.  Followup antibiotics can be administered to prevent recurrence or spreading.

I hope your little guy does well.  What a survivor!

Dana