My observation shows two differences. These differences will exist in any subgroup and is not to be considered as exclusive. 1. The American dog is more mastiffy - bigger, more bone, wider body.. 2. The Italian dog has a sharper temperament. Incidentally, it depends to a great extent on the line. Since there are many Italian bred Cane Corsi in the USA it is probably difficult to ascertain from whence they came without first-hand knowledge of the dogs.