A ganglion cyst is a fluid-filled mass that usually grows out of hand or wrist joints and has a balloon-like appearance, according to the American Academy of Orthopaedic Surgeons. The AAOS provides a labeled image of a ganglion cyst excision surgery on its website.
Ganglion cysts are not cancerous and are mostly harmless, explains the AAOS. Most ganglion cysts do not require treatment, but treatment may be necessary if the cyst interferes with normal function of the affected areas, if it causes pain, or if it creates concerns about appearance. Surgical excision is performed if non-surgical treatment options fail to remove the cyst.