Ganglion cyst aspiration - what makes the fluid inside?

Ganglion cyst: A gangling cyst arises from a joint. The fluid in the cyst is synovial, or joint, fluid.

Joint Fluid: A ganglion cyst is a collection of thick joint lubrication fluid that has gotten outside of the joint. Commonly seen on the wrist and the knee ( called a baker's cyst). The fluid is thick and doesn't aspirate well through a needle unless the needle is quite large. 90% chance it can recur. Best treatment is surgery to remove it, but still has as high as 10 % chance to recur.

Ganglion cyst: The fluid inside is made of synovial fluid. The cyst usually grows off a tendon or joint and has a stem that draws fluid from the tendon sheath or joint to fill the cyst up. The cyst can rupture and flatten out but can and will refill as long as the stem is still there.