The call just came. The report is back. It was not a mast cell tumor.
It was a plasmacytoma, a form of skin cancer but Dr B took a lot of the surrounding tissue and the report says the edges are clear.
We'll watch him carefully for the next six months, but the doctor thinks the surgery should be curative.
Just as an interesting fact, my first Portie, Bentley, had a plasmacytoma removed from his muzzle when he was a year old and it never recurred.