| Ganglion cyst | |
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Cyst on dorsum of left hand close to the wrist
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The average size of these cysts is 2.0 cm, but excised cysts of more than 5 cm have been reported. The size of the cyst may vary over time, and may increase after activity.
These cysts most frequently occur around the dorsum of the wrist and on the fingers. A common site of occurrence is along theextensor carpi radialis brevis as it passes over the dorsum of the wrist joint. Although most commonly found in the wrist, ganglion cysts also may occur in the foot.
Ganglion cysts are "commonly observed in association with the joints and tendons of the appendicular skeleton, with 88% 'in communication with the multiple small joints of the hand and wrist' and 11% with those of the foot and ankle." Most often, they are found near the wrist joint, especially at the scapho-lunate area, which accounts for 80% of all ganglion cysts.
Ganglion cysts are not limited to the hands and feet. They may occur near the knee, commonly near the cruciate ligaments, but also they may occur at the origins of thegastrocnemius tendon and anteriorly on Hoffa's infrapatellar fat pad. At the shoulder, they typically occur at the acromioclavicular joint or along the biceps tendon.
The most commonly accepted cause of ganglion cysts is the "herniation hypothesis", by which they are thought to occur as "an out-pouching or distention of a weakened portion of a joint capsule or tendon sheath." This description is based on the observations that the cysts occur close to tendons and joints, the microscopic anatomy of the cyst resembles that of the tenosynovial tissue, the fluid is similar in composition to synovial fluid, and dye injected into the joint capsule frequently ends up in the cyst, which may become enlarged after activity. Dye injected into the cyst rarely enters the joint, however, which has been attributed to the formation of an effective and one-way "check valve" allowing fluid out of the joint, but not back in. Synovial cysts, posttraumatic degeneration of connective tissue, and inflammation have been considered as the causes. Other possible mechanisms for the development of ganglion cysts include repeated mechanical stress, facet arthrosis, myxoid degeneration of periarticular fibrous tissues and liquefaction with chronic damage, increased production of hyaluronic acid by fibroblasts, and a proliferation of mesenchymal cells. Ganglion cysts also may develop independently from a joint.
Ganglion cysts are diagnosed easily, as they are visible and pliable to touch.
Radiographs in AP and lateral views should be obtained to exclude any more serious underlying pathology. Ultrasonography (US) may be used to increase diagnostic confidence in clinically suspected lesions or to depict occult cysts, because intratendinous ganglia are readily distinguished from extratendinous ganglia during dynamic US, as microscopically, ganglionic cysts are thin-walled cysts containing clear, mucinous fluid.
Other than the frequent choice to leave the cyst in place, surgical treatments remain the primary elective option for treatment of ganglion cysts. The progression of ganglion surgery worldwide is to use an arthroscopic or mini-opening method. Alternatively, a hypodermic needle may be used to drain the fluid from the cyst (via aspiration) and a corticosteroid may be injected after the cyst is empty,however, if the fluid has thickened, owing to the passage of time, this treatment is not always effective. There is a recurrence rate of approximately 50% following needle drainage (aspiration) of ganglion cysts.
One common method of treatment for a ganglion cyst has been to strike the lump with a large heavy book, causing the cyst to rupture and drain into the surrounding tissues. Historically, a Bible was the largest or only book in any given household and commonly was used for this treatment. This led to the nickname of "Bible bumps" or "Gideon's disease" for these cysts. This treatment is not now recommended.
Complications of treatment may include stiffness in the hand or location, and scar formation. Recurrence of the lesion is more common following excision of a volar ganglion cyst in the wrist. Incomplete excision that fails to include the stalk or pedicle also may lead to recurrence, as will failing to execute a layered closure of the incision.
Recurrence rate is higher in aspirated cysts than in excised ones. Ganglion cysts have been found to recur following surgery in 12% to 41% of patients.
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