one yr old yorkie has one lumpy mammary nipple

Question
I think it about time for her to go into her second heat cycle, but I notices one of her nipple areas is very lumpy and if I squeeze it, it looks as if it could be milk, but I don't think she is pregnant yet since she has not gone into heat again. Is this normal?  Her eating and sleeping habits are quite normal and she is very happy. Should I worry?

Answer
If it's one mammary I wouldn't worry too much about it. Most likely it is from her estrus cycle coming up. Are you planning on breeding her at two years of age? If you are not, then you should get her spayed soon as the longer you wait the more susceptible she will be to mammary gland cancer later on.