It happens in multiparty systems as well. All it takes is a significant portion of the population feeling like their voices are not heard, and then one of the parties taking up their banner as one part of the overall campaign (which doesn't even have to be in their new constituents' interests).

This is happening all over Europe as we speak. And even though it happens to be extreme-right atm, it doesn't have to be. We've seen extreme-left revivals in the past as well.