Dropped off of a Cave-Troll Drummer, inside Goblin-Town (Misty Mountains), on the boss level below. 11/20/2010.
Also, it's an Undamaged Cave-Troll Head, not corpse.
Take the item to the Taxidermist in the back of the taxidermy house in Bree-Town, named Clar Whitethorn. It's the forth item down on his list after right clicking on him, Cave-Troll Trophy.