There's a trick where you screw the die into the press upside down, then use a 1/2 socket and a long screw to pull the case out.
After you screw the die into the press upside down, soak the case/die in a penetrating oil. Kroil is great for this. Then place the socket over the base of the case that's sticking out of the die. Get a long screw (even a wood screw will work) and a washer and put the screw through the washer, then drop it through the socket. Now just thread the screw into the primer pocket of the case. If you want to get fancy you can drill and tap the primer pocket before hand.
The other option is to pull the decapping rod out of the die and beat the case out with a punch. That makes an awful lot of noise though!

I've never had a case stuck that bad, but I've torn the rim off of a few over the years and been pretty close! I have use the above method on a dies while teaching new reloaders the importance of proper case lubing.

Andrew