I just found a small lump on my dog's back.

[Catshrink]

It's about the size of large wart and doesn't seem to bother him when I check it out. Is this normal for dogs?

[MadHound]

1. It is probably a fatty cyst

Essentially a lump of fat. This starts happening in middle age and older dogs. If the lump isn't discolored, and doesn't start to radically grow, I wouldn't worry about it, just point it out on your next regular vet visit.

[Catshrink]

3. He's only 2 1/5 years..

I thought it might be the result of a cat whack, but it's on his back -- I'd expect to see a cat whack on his face.

[MadHound]

4. It could still be a fatty cyst

But I would get it checked out. Is your pup an inside/outside dog? By that I mean does he stay outside for lengths of time without your supervision. If so, he might have gotten into a fight with some other critter, or some cruel fool might have shot him with a BB or pellet gun.
But if the lump isn't super hard, and isn't causing your dog distress, my bet is still on a fat cyst.

[undeterred]

2. Its probably harmless

but you should have a vet check it out. The older dogs get, the more lumps and anomalies they get.

[Gidney N Cloyd]

5. Run it past your vet . Different breeds are prone toward different types of

tumors. It could be nothing.

[xchrom]

6. i learned the hard way -- always have anything

suspicious checked out thoroughly when it comes to your animal.

my old boy had to undergo chemo -- and he made it just fine -- but i let it go longer than i should have.

[MonkeyFunk]

7. Look closely

and make sure it's not a tick.