There are no instanced dungeons. There are caves, ruins, castles, crypt etc underground areas of various sizes which have dungeon-y layouts but no named mobs (loot is all small % drop from x type mobs anyway, other than boss drops).
There are 2 huge "dungeons" in the desert with very high level hard mobs which effectively require a group to make any meaningful progression, and these groups end up repeatedly killing the same set of mob spawns over and over again in a very eq1 esque manner. But again no named spawn camps.