Well, the pathology report came back yesterday. Blue's intestinal mass was diagnosed as leiomyosarcoma. The surgeon attempted to be upbeat, telling me that the margins were complete, so hopefully he got it all.
But in talking with Greg, he reminded me of the enlarged lymph nodes that were seen on ultrasound.... And it is a cancer known for metastasizing. (Another bit of somewhat good news, though: at least it wasn't in the liver.)
This is normally a cancer of older dogs. Median age at diagnosis is a bit over 10. Blue is 2 1/2. Does this mean that he's young and can fight it better? Or does this mean that it's a particularly aggressive variant of the disease? Only time will tell us, so all I can do is try to move this news to the back of my mind and enjoy our time with him, however short or long it may be. (Median survival appears to be 22 months after diagnosis.)
Ironically, in this case, it might almost be easier to have the mindset of a dog - and let the future take care of itself.