A ganglion cyst is a noncancerous lump that most commonly develops in the wrist or hand. Some occur in the ankles or feet.If a ganglion cyst presses on a nerve, it may be painful. Depending on its location, a ganglion cyst may restrict movement. ganglion cyst is a noncancerous lump that most commonly develops in the wrist or hand. Some occur in the ankles or feet.