Thanks to Miky (*) who writes a most interesting blog, we now know what this stemma I saw in Pistoia represents.
The pig/swine is the attribute of the Cancellieri family, who once figured in the political life of Tuscany. This particular depiction can be found on the facade of the palace that bears their name.
If heraldry is of interest to you, follow this link and run the Italian through a translator. Cancellieri