Do you have a lump on your wrist that comes and goes, or increases and decreases in size? Then you may have a common benign mass that occurs near joints or tendons called a ganglion cyst.
Ganglion cysts are often firm and non-tender, although they may be tender if displacing a structure such as a nerve, or getting in the way of joint motion.
How can you tell if your wrist mass is a cyst? Your doctor or a hand surgeon is the best one to tell you,
possibly with the use of ultrasound, but if you want to try to figure it out at home, get a flashlight and shine it on the mass.