The culture of Egypt and Mesopotamia/Levant have become the Mediterranean culture, so the term Mesoandean would make sense considering the similarities of the Incas and Aztecs?
To better answer your question, what similarities are you seeing between Aztec and Inca cultures?
In the meantime, you may be interested in our FAQ section on Pre-columbian trade, and particularly this answer from /u/400-rabbits. In short, while contact did happen between both areas, and with significant results, it was uncommon and often through intermediates. Keep in mind that Cuzco is 3000 miles from Tenochtitlan. We can expect cultural continuity between them as much as we could between Egypt and Nepal.