Difference between AC brotherhood and AC brotherhood (expansion pack)?

ok what's the different between assassin's creed brotherhood and assassin's creed brotherhood(expansion pack). I saw them on ebay.Some say normal and some expansion pack. Does this mean it has the da vinci disapearence expansion pack? and don't tell me something stupid like assassin's creed brotherhood is a whole other game from assassin's creed 2 cuz thats not what i'm asking