Dupuytren disease or ganglion cyst, how to know?

Ganglions Have Fluid: A ganglion cyst will light up in the dark with a light (transillumination). Ganglion cysts can be aspirated or ruputured. Dupuyten's is hard and tend be lumps in a linear chain that goes on to contract the fingers.

Dupuytrens is: more superficial in the skin and the tissue just below it. It feels firm as a nodule in the skin. A ganglion in the palm, most common is one off the tendon sheath near the finger palm crease, is deeper, rounder or spherical and at times moves within the layer just below the fascia and subcutaneous tissue and does not "move" with skin./admittedly a learned skill to differentiate these accurately

Firmness: Ganglions are soft and fluid filled. Dup is hard nodules and cords. New treatments include needle aponeurotomy and xiaflex (collagenase clostridium histolyticum). http://centraljerseyhand.com