Eggs can melt?
Eggs are not homogeneous substances or mixtures for what the word "melt" even makes sense. But also, most of an egg's mass is composed of substances that suffer chemical transformations in much lower temperatures than other parts can melt (at any pressure).
Even if there is no oxygen on your environment, an egg will decompose itself before all of it is molten.
This paper seems to at least hint at the possibility: