There were already good transatlantic fares to MXP this winter across several airlines. On top of that, AA had a targeted E-mail promotion for 20% off fares to Europe. Since MXP is AA's only wintertime destination in Italy, that could be what's going on here with the OP.

I received the targeted promotion and snapped up a seat to MXP and will go in February. I plan to spend a few days in Milan, a city I don't know but would like to know better, and will head to Turin for a couple of days.