Yes, I have a small tendon sheath ganglion cyst in my right pinkie.  I went to a hand surgeon, and he said it would be easy to remove, if it bothered me. 

The surgeon wasn't sure what causes them, but sometimes they can happen as a joint heals after an injury.  I suspect it happened while snowboarding, and the surgeon said it most likely wasn't from drumming.

It's in the first knuckle, where the pinkie meets the hand.  It only bothers me if I over use the hand, or if something physically puts pressure on the joint.  I opted not to have it removed, unless it really becomes a problem.

I would definitely go to a doctor for any kind of wrist pain.  There are too many muscles and tendons in there, and our wrists are so essential to what we do!  Repetitive motion injuries are common among drummers, and sometimes the only treatment is to rest.