I have heard this phrase use like a greeting and wonder if it can be used as an alternative to Que Pasa?
The way it is written is wrong anyway, but "¿Qué entonces?" can be regarded as an option in some countries (Spain is not one of them). "¿Qué pasa?" is used in Spain, but these common expressions vary a lot from country to country.
The way i understood it was like qué pasa - what's up? like a greeting qué paso - what happened?
I believe I've heard ¿Qué pasó? as well.