The vet called yesterday and said Addie did indeed have a malignant neurofibrosarcoma but because she took so much tissue from the surrounding area, the histopathology report came back indicating she had "clean borders" meaning she got all the cancer cells. When she told me that, I started to tear up because it was such good news. I really didn't know what I would have done if she said further treatment would be needed, i.e. radiation/chemo. But now, I don't have to think about it.
Apparently, Springer Spaniels are one of the breeds predisposed to these types of tumors so in the future, if I feel any more bumps, I need to get her back in because the chance for reoccurence is pretty good.
Bad news is she has been licking the wound so she will now be wearing the e-collar for another week until the stitches are removed.
Big sigh of relief....