Ok, so I am confused. Through my research, I was under the impression that the Cane Corso is the Cane Corso & that it is the "Italian Mastiff." I didn't see anywhere that said it some are "American Mastiffs" & some are "Italian Mastiffs."
Now I do understand that different bloodlines are popular in different countries (as here in American we tend to ruin every breed we get our hands one, even the ones created in our own country), but to say they are two different breeds is wrong. That's like saying there is an American Rottweiler & a German Rottweiler. The truth is, there is only 1 Rottweiler. Yet there are certain bloodlines that each country favors above the others. However, "American", "German", "Italian", etc. are NOT bloodlines.
As far as the difference in looks go, different strains & what they were bred for will determine the look of a dog. It's always been said that "form follows function" & that's why so many dogs within a breed can look a little bit different. Take Neos for example. Neopolitan Mastiffs are not truly oversized, lumbering idiots with so many wrinkles it can't even see. This is just what show breeders fancy. Working breeders (for the few that are still using this breed as a working guard dog) wouldn't touch those oversized too wrinkled dogs for anything. I've seen some Neos that come from old strains, & although they are very similar to the others depicted, they don't have near as many wrinkles nor are they as large. Also look at the Shar Pei. The Shar Pei used to be a dog that was known for it's wrinkles--on it's head only b/c as they grew, the body wrinkles became less apparent or they disappeared all together. However, b/c people love the squishy, wrinkly look, they totally disregarded history & began breeding dogs solely for their wrinkled bodies. Peis today have much more wrinkles than they did 30 years ago.
The same goes for Corsos. I very good friend of mine (& client at our clinic), owns & raises them. His dogs are absolutely amazing. Looks wise, they do have a couple wrinkles here & there (mainly on the forehead), but they are no way covered in them. They are tight bodied, tight lipped animals that are wary of strangers yet are comfortable as long as their owner is comfortable in someone's presence. This guy OFA's ALL his dogs--hips, cardia, & thyroid--as this breed has now become the byb dream dog & the quality out there is amazingly crappy. Most of his dogs are tolerant of our handling & some even outright love coming to see us (I'm a vet tech).
My advice is to go back to the roots of the breed & find breeders that are sticking to them. To many people breed dogs for looks nowadays, & that's the furthest thing you should ever want.
Good luck!
Btw, I've got a Shar Pei/Cane Corso mix. He's a pain in my ass, so if you want him.........