Medically reviewed by Lauren Schlanger, MD Key Takeaways A ganglion cyst is the most common cause of a lump on your hand or wrist and often feels round or oval. A carpal boss is a hard, bone-like lump ...

What Is a Subchondral Bone Cyst? It's a fluid-filled sac that forms in one or both of the bones that make up a joint. They're especially common at the knee or hip. The cysts show up just under the ...