What is it?
According to E Hand.com it is a ganglion. I love the explanation of how it can be this or that and caused by this or that and may or may not be an issue. I may or may not lose my finger nail. I can't help but laugh. I do figure I may or may not survive the procedure but will take a wild chance and say I will! Who knows, I may or may not be back as soon as tomorrow afternoon! More likely Tuesday, however.
This is how E Hand explains it:
In the hand, a ganglion is a particular type of lump which shows up next to a joint or a tendon. Inside, it is like a balloon filled with a thick liquid. It may be soft or hard, may or may not be painful, and may get bigger or smaller on its own. It may also be referred to as a mucous cyst, a mucinous cyst or a synovial cyst.I'm seeing more of my Doctor these days than Bacchus is his. I'm using the time for a bit of a tune up. After this little snippet is over, we tackle the arthritic back. One more time. Sigh.
What caused it?
Normally, joints and tendons are lubricated by a special liquid which is sealed in a small compartment. Sometimes, because of arthritis, an injury, or just for no good reason, a leak occurs from the compartment. Now, the liquid is thick, like honey, and if the hole is small, it can be like having a pinhole in a tube of toothpaste - when you squeeze the tube, even though the hole is small and the toothpaste is thick, it will leak out - and once it is out, there is no way it can go back in on its own. It works almost like a one way valve, and fills up a little balloon next to the area of the leak. When we use our hands for normal activities, our joints squeeze and create a tremendous pressure in the lubricating compartment - this can pump up a balloon leak with so much pressure that it feels as hard as a bone.
The lubricating liquid has special proteins dissolved in it which make it thick and also make it hard for the body to absorb it when it has leaked out. The body tries to absorb the liquid, but may only be able to draw out the water, making it even more thick. Usually, by the time the lump is big enough to see, the liquid has gotten to be as thick as jelly.