a ghetto pretty boy is one of the types of pretty boys. They are basically a regular pretty boy with an urban (ghetto) style and flare.
A ghetto pretty boy in general is usually a teenage boy with a clean cut appearance with a slight ghetto touch. So say instead of wearing preppy type brands, they would wear brands like South Pole, Ecko, Sean John, etc.
girl 1: Omg! Frankie J and Usher are so hot!
girl 2: Now that's what I call a real ghetto pretty boy.