I had one on my left wrist and it went away on it's own after about 5 years. After doing some research and reading I found out about being able to burst the sac internally. I have successfully rid myself of this nusance 3 times. first 2 times I slammed it against my desk at home. The third time it was against a brick wall. You really need to massage and cool with ice as much as possible before attempting this. I am no physician but they do go away, either on their own or by force. Cause of this problem is unknown.