This is rare footage of the needle aspiration of a ganglion cyst under ultrasound. In fact, this is the first ganglion cyst that I have ever aspirated in the emergency department and the gelatinous contents of the ganglion cyst was truly impressive and nothing like anything I've seen in the past. Again, be sure to sign up for the USAHEALTH Videos YouTube channel. Eventually, we will not be sharing as many videos between the two channels.
Here is what Medscape says: Hyaluronic acid predominates the mucopolysaccharides that make up the fluid within the cyst’s cavity, whereas collagen fibers and fibrocytes make up the wall lining.  The development of these cysts is histologically observable beginning with swollen collagen fibers and fibrocytes, followed by a degeneration and liquefaction of these elements, a termination of degeneration, and, lastly, a proliferation of the connective tissue, resulting in a border that is dense in texture.  https://emedicine.medscape.com/article/1243454-overview#showall