are the most commonmass or lump in the hand. They are not cancerous and, in most cases, are harmless
. They occur in various locations, but most frequently develop on the back of the wrist. These fluid-filled cysts can quickly appear, disappear, and change size.
The cause is unknown, but it is thought that small tears in the tendon membrane or joint capsule allow the contents to squeeze out. In many cases, ganglion cysts go away by themselves without the need for medical treatment. Treatment options include surgery
or draining the cyst with a needle.