Bump on dogs leg

I discovered a small quarter inch bump on my dogs leg. It’s very hard, it feels like it may be a cyst but i’m unsure. 

Hello!  The fact is, that your vet is unlikely to be able to diagnose this just by looking.  Sometimes with a lump, one can suggest what it's highly likely to be, for example if this was in the position of the extra pad on the back of the leg and the same on both sides, you would have a pretty conclusive answer.  But usually, a sample will be needed in order to identify an irregular lump.  In the old days, experienced vets used to try to predict the answer from the outside but we don't do that any more, because the rests of guessing were shown to be very unreliablefor the vast majority of lumps.  We reccommend getti g it checked and sampled or removed if appropriate.

The 'results' of guessing were shown to be unreliable.  Autocorrected to 'rests' -  with my apologies!