Chombi1 

Maybe a prototype contracted out then passed over by Masi, thus the big hole on the BB and absence of serial numbers.....I dunno, just another guess....
The bike could have an interesting history, but unless there is some feature to it that will make it somehow unique (or evidence it was under a master builder's torch because of excellent brazing and lug preparation) to make it endearing to collectors of really rare bikes, it might just end up as a forgotten "Masi", maybe for good reason.
At this point, I can't really see much of the bike in the pics yet, so it comes through initially as being rather plain looking, as other have also hinted at....