lump under nipple on female dog

Question
I have an 11 year old female red setter cross, who has been spayed and never had puppies.She is fine and well, but two days ago I noticed a lump under one of her nipples. I is about 1-2 inches across and feels quite soft. The nipple itself has a scab on it. The lump doesn't hurt her and I haven't noticed it before and neither have the children, so I don't think it has been there long. What do you think it could be and should I give her a few days to see if it goes down before I take her to the vets?

Answer
Depending on her age when she was spayed she could have a small mammary tumor or just a fatty tumor. The first one is serious, the second not so much.

Either way this needs to be looked at by the vet. If it is a mammary tumor it is really important to remove it right away. If it is a fatty tumor, the smaller they are when you remove them the better. They (fatty tumors) are not cancerous and do not spread but they can get more.

Mammary tumors can spread and can metastasize. That is why it needs to be looked at pronto.
I hope it's a fatty tumor. They are much more common.
Please let me know what you find out.