All dragons in WoW (at least that I have seen) have a set of "main" horns. They resemble a mountain goats or antelopes.
Malygos, a full grown wyrm and leader of his dragon flight is missing these horns. Sure, he has all sorts of spikes shooting out of his face, but if you look at any other dragon model you'll see the set of "main" horns I am referring to.
Where did Maly misplace his horns?!?!