I have a few of these in high school and college - always on the top side of the hand/wrist. They always went away with the good hard smash with a book.

After I had my daughter (almost 12 years ago), I got one that wouldn't go away at all. (As CA notes, maybe it was stress - I had been unemployed while pregnant, got a job, gave birth, etc.). Anyway, the book didn't work and aspiration was worthless and it was right back so I opted for surgery.

The surgery was great (other than the fact I am allergic to any sort of anaesthesia and always throw up as they wake me up ). I have had no lingering effects at all - the only sign of any issue is a small scar. And I like scars!

I just want to throw that out to let you know the surgery doesn't have to come with ROM side effects, etc. The fact yours in on the palm side sure suggests to me it would be more painful than mine while it is there. And perhaps the doctor might suggest some PT type exercises after it's healed to prevent any sort of movement restrictions.

And I had ALL my ganglions before I ever set my butt on a bike. Since I started riding, I have had not a one. So maybe it's the cause of yours - but then again maybe not. Everyone's (including mine) anecdotal evidence is interesting, but really doesn't get to the root of the cause of yours. But it's really nothing to worry about, anyway. It's a minor thing, and whether you deal with it with a book or a needle or go under the knife, you're likely to be fine.