Ganglion cyst

A ganglion cyst, known as simply a ganglion to most, is a harmless fluid-filled sac that can pop up anywhere on the body but is common around the joints and tendons of the hand and wrist.

It's unknown what causes this, but it develops from a neighbouring joint or from the structure surrounding certain tendons and is filled with synovial fluid – the same substance found in joints to keep them lubricated.

While lumps and bumps often cause alarm, ganglions pose no risk to your health and people are often more bothered by the appearance than any symptoms. Rarely you may get an aching or difficulty with certain movements if the ganglion is around a joint.