The " bump" is officially a lipoma.

Boy, it seemed like it took forever for the lab results to come back. According to Antech, the cells are adipose. (I think that's what the vet said. I'll get a copy of the report the next time I'm down there.) He seemed comfortable with that report, although he said that it's never a good idea to totally assume that it's not gonna turn into something worse. For now, he thinks that occasional monitoring (aspirations) and checking growth will be sufficient. Thank goodness. Lipomas are supposed to be slow growing, although this one wasn't noticeable when Scruffy was shaved for the first time last year and it's certainly a good size now. At least now I know where to look and what to watch.