"Mixoid Cyst Finger" Quite a lot and a lot on Images as well.
I had one for a couple of years. It got quite big and them did a miraculous disappearance virtually overnight. GP told me they are quite common near arthritic finger joints.
Could be a ganglion - a kind of cyst - I remember my mother having one and the doc hit it with a copy of Grey's Anatomy, he said it should have been a Bible, but he didn't have one to hand!
Failing that, does that area get rubbed alot? I noticed that i had a small lump on the outside edge of my right index finger, then when I was peeling potatoes I realised it's where the the knifeblade 'sits' right next to the haft and it rubs me causing like a ridge of hard skin
Don't do anything to it if it looks like the picture. I tried and mine got infected. I don't think it is a ganglion. Mine grew quite large and started covering the nail, the nail then grew a funny shape. Then suddently it went.
I don't think it is a sign necessarily that you will get arthritis, but, as I said, people with arthritic fingers often get them.