Digital myxoid cyst excision surgery. A digital myxoid cyst is a benign (non-cancerous) cyst filled with a jelly-like substance. It is thought to form from the degeneration of a joint and is often associated with osteoarthritis of the nearest joint. The cysts are usually asymptomatic, but can be painful. Many cysts will disappear on their own, but drainage or surgical removal can be used to treat large or painful cysts.