enlarged nipple

I have about an 8-year-old female miniature dachshund.  She is spayed, but was already pregnant at age 2 when I got her.  

Last Sunday I found that she had what looked like an inflamed nipple, just one nipple.  Others are shriveled and dark, this one is enlarged, soft, and pink.  It does not seem to cause her pain when I handle the nipple.  There is no lump in the tissue under the nipple, or in the nipple itself.  

I took her to the vet on Tuesday.  My vet said she did not know what it could be, possibly an injury, or even a benign tumor, but it did not fit the picture of cancer, as there is no lump, no skin color changes, etc.  She did offer to remove it if I want to.  

Since then the nipple has grown noticeably.  I am wondering what this might be?  

[Aleda M Cheng, D.V.M., C.V.A]

It should be biopsied for a definite diagnosis.  If the enlarged nipple is small enough it could be removed with a local anesthetic and sedation, possibly, but whatever the surgical method please have it biopsied.

[amity150]

Thank you.  I will call the vet tomorrow and ask her to do that.  I did not want to do anything unnecessary because i didn't want to put her through general anesthesia.  But I think this is necessary.  

If I can ask one more question, can skin cancer on a dog be removed with cryotherapy?  In other words, since that seems to be the worst this could be, can it just be frozen off?