Hand and wrist ganglia account for 50% to 70% of all hand masses. The ganglion is a benign, mucin-filled cyst found in relation to a joint, ligament, or tendon. It is typically filled from the joint through a tortuous duct or “stalk” that functions as a valve directing the flow of fluid. The mucin itself contains high concentrations of hyaluronic acid as well as glucosamine, albumin, and globulin [1]. When it is used to describe ganglia, the term synovial cyst is actually a misnomer because ganglion cysts do not contain synovial fluid and are not true cysts lined by epithelium but rather by flat cells. The etiology of ganglia remains a mystery, although many think that ligamentous degeneration or trauma plays an important role [1,2].

By far, the most common location for a ganglion is the dorsal wrist (Fig. 32.1), with the pedicle arising from the scapholunate ligament in virtually all cases. Only 20% of ganglia are found on the volar wrist (Fig. 32.2). This type may originate from either the radioscaphoid or scaphotrapezial joint. Alternatively, ganglia can occur near the joints of the finger. One subtype of hand-wrist ganglia is the “occult” cyst, which is not palpable on physical examination.

f32-01-9781455775774 — FIGURE 32.1 Dorsal wrist ganglion. The mass is typically found overlying the scapholunate area in the center of the wrist.

f32-02-9781455775774 — FIGURE 32.2 Clinical appearance of a volar wrist ganglion.

Ganglion cysts occur more commonly in women, usually between the ages of 20 and 30 years. However, they can develop in either sex at any age. Ganglia of childhood usually resolve spontaneously during the course of 1 year [3]. The most commonly seen ganglion of the elderly, the mucous cyst, arises from an arthritic distal interphalangeal joint (Fig. 32.3).

f32-03-9781455775774 — FIGURE 32.3 Mucous cyst. This ganglion originates from the distal interphalangeal joint. Pressure on the nail matrix by the cyst may produce flattening of the nail plate, as is seen here.

Other common types of ganglia in the hand include the retinacular cyst (flexor tendon sheath ganglion; Fig. 32.4), proximal interphalangeal joint ganglion, and first extensor compartment cyst associated with de Quervain tenosynovitis. Less common ganglia include cysts within the extensor tendons or carpal bones (intraosseous) and those associated with a second or third carpometacarpal boss (arthritic spur). Rarely, ganglia within the carpal tunnel or Guyon canal can produce carpal tunnel syndrome or ulnar neuropathy, respectively.

f32-04-9781455775774 — FIGURE 32.4 Retinacular cyst. This ganglion originates from the flexor tendon sheath.

As noted, the cause of ganglion cyst formation is not known, but there may be a link to light, repetitive activity, demonstrated by an increased incidence in typists, musicians, and draftsmen. Interestingly, there is no increased risk in heavy laborers, who bear a greater load on their wrists. Wrist instability has also been discussed as both a possible cause and an effect of the disease. Overall, there is a history of trauma in 10% to 30% of people presenting with the disease [2].

Symptoms

Patients with a wrist ganglion usually present with a painless wrist or hand mass of variable duration. The cyst may fluctuate in size or disappear altogether for a time. Pain and weakness of grip are occasional presenting symptoms; however, an underlying concern about the appearance or seriousness of the problem is usually the reason for seeking medical attention. The pain, when present, is most often described as aching and aggravated by certain motions. With dorsal wrist ganglia, patients often complain of discomfort as the wrist is forcefully extended (e.g., when pushing up from a chair). Interestingly, dorsal wrist pain may be the principal complaint of patients with an occult dorsal wrist ganglion, which is not readily visible. The wrist pain usually subsides as the mass enlarges.

With a retinacular cyst, patients usually complain of slight discomfort when gripping, for example, a racket handle or shopping cart. Patients whose complaints of pain are primarily related to de Quervain tenosynovitis (see Chapter 28) may notice a bump over the radial styloid area. Pain with grip is also a complaint of patients with a carpometacarpal boss. On occasion, the digital extensor tendons may jump over the cyst with radioulnar deviation. Mucous cysts can drain spontaneously and can also produce nail deformity, either of which may be a presenting complaint. Symptoms identical to those of carpal tunnel syndrome will be noted by patients with a carpal tunnel ganglion. A ganglion in the Guyon canal will produce hand weakness (due to loss of intrinsic function) and may produce numbness in the ring and small fingers.