Ganglions 

Ganglions are among the most common tumors of the hand and wrist. For the most part, they are asymptomatic masses that are primarily cosmetic rather than functional disturbances. In most instances, observation is the only management necessary. However, some ganglions can exert a mass effect on nearby structures, such as arteries, veins, tendons, and nerves. The impingement of such structures can cause pain, triggering of tendons, and vascular compromise. In these instances, the patient often seeks surgical attention.^{[1, 2, 3, 4]}

The image below depicts a ganglion cyst.

People have been seeking treatment for ganglions for many centuries. Historically, treatment consisted of crushing the ganglion with a heavy object (eg, a Bible). Often, a firm strike with a heavy object was all that was needed to cure the patient. Now, simple observation, aspiration, and surgical excision are the treatment modalities of choice.

Many ganglions can be managed with mere observation. However, each type of ganglion can cause local symptoms depending on its anatomic location.

Frequency

Ganglions in general represent 50-70% of all soft-tissue tumors of the hand and wrist. The prevalence in women is 3 times greater than that in men. Most ganglions occur in persons aged 10-40 years, with a range from childhood to the ninth decade of life.

These tumors may occur in a variety of locations. Mucous cysts are ganglions of the distal interphalangeal (DIP) joint that occur primarily in persons aged 40-70 years. These also occur more commonly in females than in males.

The etiology of ganglions is unknown. Theories include mucoid degeneration and trauma. Some patients (< 10%) recall minor or major trauma to the area prior to development of the mass. No known occupational risk factors exist. Mucous cysts and some other ganglions are associated with degenerative joint disease.

Hippocrates described ganglions as "knots of tissue containing mucoid flesh." Since this description, several hypotheses have been proposed. These include the following:

• Synovial herniation or rupture through the tendon sheath (Eller, 1746)
• Synovial dermoid or rest due to "arthrogenesis blastoma cell nests" or embryonic periarticular tissue (Hoeftman, 1876)
• New growths from synovial membranes (Henle, 1847)
• Modifications of bursae or degenerative cysts (Vogt, 1881)

The theory of mucoid degeneration offered by Ledderhose in 1893 was widely accepted. In Green's most recent edition of Operative Hand Surgery, however, this theory is replaced with a theory based on microtrauma and hyaluronic acid production.^[3] Local tissue trauma or irritation is postulated to cause production of hyaluronic acid at the synovial-capsular interface. The hyaluronic acid creates small mucin lakes that coalesce into subcutaneous cysts with stalks or ganglions.

Ganglions are tumors that present adjacent to joints or tendons. The most common sites for ganglions are the dorsal aspect of the wrist near the scapholunate (SL) joint (60-70%), the volar wrist near the radioscaphoid joint or the pisotriquetral joint (18-20%), and the volar retinaculum between the A1 and A2 pulleys (10-12%). Mucous cysts occur over the dorsal digit at the DIP joint level. Other sites include the carpometacarpal (CMC) joint, the extensor tendons (especially associated with the first dorsal compartment), the carpal tunnel, and the Guyon canal. Ganglions may also arise within bone; these are called intraosseous ganglion cysts.

Ganglions are usually minimally symptomatic. However, depending on the location of the cyst, patients may present with a myriad of symptoms such as dull aching pain, change in size, spontaneous drainage, and sensory nerve dysfunction. Specific symptoms for each type of ganglion are described next.

Dorsal wrist ganglions

Dorsal wrist ganglions typically present in proximity to the SL interosseous ligament. Approximately 75% of dorsal wrist ganglions are connected to the radiocarpal joint through a stalk from the SL ligament. Some ganglions may present at a site distant to the SL ligament, but they are attached to the ligament by a long pedicle. Careful palpation over the cyst and pedicle often reveals the extent of the cyst and the direction in which it is traveling. Most are asymptomatic masses that change in size. Some patients may present with pain and tenderness due to compression of the posterior interosseous nerve (PIN) or the superficial radial nerve. The mass itself is compressible, subcutaneous, transilluminating, and slightly mobile without associated skin changes.

Differential diagnoses include the following:

• Tenosynovitis
• Infection
• Extensor digitorum brevis manus muscle belly
• Proximal pole of scaphoid (dorsiflexed intercalated segment instability [DISI])
• Proximal pole of lunate (volar-flexed intercalated segment instability [VISI])
• Scaphotrapezial arthritis
• CMC boss
• Venous aneurysm
• Lipoma
• Neuroma
• Hamartoma
• Sarcoma

Occult dorsal ganglions

Patients with occult ganglions can present with the same symptoms as those with dorsal ganglions without a clinically evident mass. These ganglions are small and not palpable. Patients often experience pain, and these lesions may go undiagnosed for extended periods.^[5]

Volar wrist ganglions

Two thirds of volar wrist ganglions come from the radioscaphoid joint and the remaining third from the scaphotrapezial joint. They rarely occur at the pisotriquetral joint. The cyst usually appears between the radial artery and the flexor carpi radialis (FCR). The cyst appears small clinically, but considerable extension may be found at the time of surgery. These ganglions have been found to track along the thenar muscles or along the FCR, they may extend into the carpal tunnel, and they have multiple appendages intertwined with the radial artery.

Patients present with pain and/or tenderness at the site of the ganglion and a palpable cyst. They may have sensory symptoms (palmar cutaneous branch of the median nerve) or, less commonly, motor nerve dysfunction.

Differential diagnoses include the following:

• Tenosynovitis
• Infection
• Carpal osteoarthritis
• Lipoma
• Sarcoma
• Radial artery aneurysms or arteriovenous malformations
• Hamartoma
• Intraneural cysts

Volar retinacular ganglion

Volar retinacular (flexor tendon sheath) ganglion arises from the A1 or A2 pulley of the flexor tendon sheath and presents as a small (3 to 10 mm), firm, tender, and mobile mass near the proximal digital crease or the metacarpophalangeal (MCP) joint. The mass does not move with the tendon. Patients may have associated paresthesias of the involved digit secondary to pressure on the digital nerve. The lesion may also be associated with stenosing tenosynovitis. The diagnosis is made based on physical examination findings.

Differential diagnoses include the following:

• Epidermoid inclusion cyst
• Giant cell tumor of the tendon sheath
• Foreign-body granuloma
• Lipoma
• Trigger finger
• Neurilemoma

Mucous cyst

The mucous cyst may be heralded by a groove in the nail bed and usually presents as a 3- to 5-mm cyst eccentrically located at the DIP between the dorsal distal joint crease and the eponychium. The mass is firm, is minimally mobile, and can be transilluminated. Mucous cysts are associated with Heberden nodes and osteophytes. A mucous cyst may be ruptured on presentation.

Differential diagnoses include the following:

• Heberden nodes
• Gout
• Giant cell tumor of the tendon sheath

CMC boss

This lesion is not a true ganglion cyst but a large spur that develops most frequently at the base of the second and third CMC joints in response to osteoarthritis. It appears as a firm, bony, nonmobile, tender mass on the dorsum of hand. Many patients are asymptomatic. Others may experience dull aching pain. A palpable ganglion is associated with a boss in 30% of cases. Some consider trauma to be the cause of the lesion.

Proximal interphalangeal joint ganglion

A proximal interphalangeal (PIP) ganglion is similar to the mucous cyst of the DIP. A 3- to 5-mm mass arises along either side of the extensor tendon at the PIP joint. Usually, the mass pierces through the oblique fibers between the central slip and the lateral band. Patients may present with pain and limited range of motion.

Extensor tendon ganglion

The extensor tendon ganglion primarily occurs dorsally over the metacarpal joints as a subcutaneous mass. It can be tender and cause a dull ache, as well as snapping of the tendon with motion.

Differential diagnoses include the following:

• Giant cell tumor of the tendon sheath
• Tenosynovitis
• Extensor digiti brevis manus muscle belly
• Dorsal wrist ganglion
• CMC boss

Dorsal retinacular ganglion

This ganglion lies within the first dorsal compartment and often is associated with de Quervain stenosing tenosynovitis. The ganglion is attached to the first dorsal extensor compartment.

Carpal tunnel ganglion

Ganglions can arise within the carpal tunnel, compressing the median nerve and causing carpal tunnel syndrome. Some of the volar wrist ganglions have been known to extend into the carpal tunnel as well.^[6]

Ulnar canal ganglions

Ganglions within the Guyon canal can cause compression of the ulnar nerve, causing sensory and motor disturbances. These ganglions seem to arise form the hamate and travel through the hypothenar muscles to the canal. These ganglions can cause atrophy of the interosseous muscles by compressing the motor branch of the ulnar nerve. When suspected, these ganglions should be removed early to prevent permanent damage.

Intraosseous ganglion cysts

These ganglions represent rare incidental radiographic findings. They can, however, be a cause of dull, aching wrist pain. When discovered, all other possible diagnoses should be pursued prior to diagnosing an intraosseous ganglion as the source of the wrist pain. The scaphoid and lunate are most commonly affected. Interosseous ganglions also are known to occur in the other carpal bones, metacarpals, phalanges, and distal ulna. They may have an etiology distinctly different from that of soft-tissue ganglions.^[7]

Differential diagnoses include the following:

• Simple bone cyst
• Aneurysmal bone cyst
• Osteoid osteoma
• Osteoblastoma
• Enchondroma
• Chondroblastoma
• Giant cell tumor
• Nonossifying fibroma
• Chondromyxoid fibroma

All of the ganglions described above are benign lesions. For most patients, observation, reassurance, or aspiration and/or injection suffice for treatment. However, in some cases, ganglions cause enough discomfort or dysfunction that surgical treatment is desired by the patient. In these cases, the ganglion may be situated close to a sensory or motor nerve, but more commonly, the pain results from the mass effect. In patients presenting with skin breakdown, nail deformity, or repeated episodes of drainage caused by DIP joint mucous cysts, surgical treatment should be considered.

See Clinical.