Introduction
Anatomy
Symptoms
Diagnosis
Non-surgical treatment
Surgical treatment
Ganglion cyst is a fluid-filled swelling that usually develops over the back of the hand or wrist. It can appear as a firm cyst swelling or as a tense, solid-feeling hard mass.
Ganglion cysts may vary in size but they are not cancerous and will not spread to other parts of the body.
Ganglion cysts are found mostly on both sides of the wrist, on fingers and, occasionally, in the foot and ankle.
Doctors don't know why ganglion cysts develop. One theory is that ganglion cysts are formed when connective tissue surrounding joints or tendon sheaths degenerate or are damaged by frictional wear and tear. It appears as a pouch filled with fluid in areas such as small joints of the wrist, or within the fibrous sheath that surrounds the tendons in the wrist and fingers.
The fluid in the ganglion is the same as the normal joint fluid found within a joint cavity or within a tendon sheath. The fluid can become gelatinous over time.
Most ganglions have no symptoms. It arises as a solitary or a lobulated swelling near a joint or on the course of a tendon sheath. The mass can grow in size with time, or occasionally shrink or totally disappear. It can be soft, firm or solidly hard, depending on the tension of the fluid in the cyst.
Pain should not be a main feature but the ganglion may produce feelings of tightness or localised pressure to the joint, depending on the joint movement. Occasionally it may produce pressure or irritation to neighbouring structures like the wrist’s cutaneous sensory nerve.
There are certain predisposed anatomical sites e.g: the mid-dorsum of the wrist under the extensor tendons and the volar surface of the wrist near the radial pulse.
Occasionally, ganglion cysts that arise from tendon sheaths can interfere with the movement of the affected tendon and may account for catching or triggering in some finger movement
Ganglion cysts usually do not produce any shadows on routine X rays. Ultrasound may demonstrate a homogenous cystic structure. Further imaging with MRI or CT scan may be indicated when the diagnosis is not certain.
While many lumps around the wrist and hand are ganglion cysts, there are conditions – including subcutaneous lipoma, giant cell tumor of the tendon sheath, some chronic infections of the joints or the tendon sheaths – that can present as lumps around the wrist. The examining doctor has to exclude other possible pathologies before reassuring the patient.
Sometimes, ganglion cysts go away with no treatment. However, most of the time they may remain the same. Some cysts have one-way valves that allow fluid to enter the cyst easily but prevents it from escaping. In this instance, the size will grow larger and it will behave as a hard swelling. Occasionally some ganglions rupture spontanously and the fluid will get absorbed.
When the ganglion cyst becomes large enough, it may put pressure on surrounding structures at certain positions on the joint. If it becomes a nuisance to the patient or if there is uncertainty about the diagnosis, surgical excision may be indicated.
There are several treatment options. Aspiration of the ganglion cyst with a needle may work. However, the gelatinous fluid within the cyst does not always come through a needle effectively so a needle with a bigger bore should be used. Furthermore, this treatment leaves the cyst wall behind and the ganglion cyst will recur in 70% of cases.
A more definitive treatment is to remove the ganglion cyst with a surgical procedure. In surgery, the wrist ganglion and the connection to the joint or tendon sheath (the cyst pedicle ) that supplied the fluid are removed. While this usually is effective, a small percentage of surgically removed wrist ganglions will still recur. Careful dissection under a bloodless field is mandatory in order to avoid inadvertent injury to the sourrounding structures or to prevent leaving behind a ganglion pedicle for future recurrence.
In the case of the wrist joint, it is made up of many small joints and a new ganglion may arise from joints adjacent to the one that has been treated. In that circumstance, it is a new ganglion cyst rather than a recurrence.
Dr. KOO, Siu-cheong