Digital Mucous Cyst Treatment & Management

Medical care for digital mucous cysts (DMCs) includes the following:

• Soaks

• Local heat

• Massage

• Occlusive treatment with topical steroids and Cordran tape

• Intralesional corticosteroids

• Home remedies - Salves, poultices, and plasters

• Application of heparin cream

• Silver nitrate

• Chemical cauterization with phenol

• Sclerotherapy with polidocanol ^[12]

• Digital compression, if the cyst is soft and located over a bony prominence

• Striking with a large book (potential for unintended trauma)

• X-ray therapy and radium irradiation (of historical interest only)

In a study of about 100 patients, surgery yielded the highest cure rate (95%) compared with sclerotherapy (77%), cryotherapy (72%), corticosteroid injection (61%), and expression of cyst contents (39%) (P< .001). ^[13]

The most conservative surgical intervention entails multiple episodes of needling the cyst with a wide-bore needle until resolution is achieved. An appropriately trained patient may continue the repeated drainage and scarification required by this method at home. ^[14]

Another technique is cyst aspiration with a large-bore needle, followed by instillation of corticosteroids (triamcinolone, hydrocortisone, betamethasone) with or without lidocaine. Some practitioners prefer to inject proteolytic agents, such as hyaluronidase, in lieu of steroids, but this may be potentially more risky given the communication of the cyst with the joint. ^[15]  Corticosteroids may be of benefit in the spectrum of ganglionlike cysts of the digits. ^[16]

Cryosurgery has been used to treat digital mucous cysts. Carbon dioxide snow, cryoprobes, and the intermittent spray technique have been used. ^[17]

Sclerotherapy was considered a quick and effective method of treatment. ^[18] Among the sclerosants infused were Morton fluid, iodine and carbolic acid, sodium morrhuate, ethanolamine, sodium tetradecyl, and polidocanol. Some consider sclerotherapy a dangerous approach because of the potential for extravasation of the chemical into the joint or tendon sheath. However, a 2008 study reported effective treatment of digital mucous cysts with percutaneous sclerotherapy using polidocanol. ^[19]

Curettage of the cyst may be attempted, and this may or may not be combined with electrodesiccation. Caution should be exercised to reduce the risk of scar.

High-intensity light sources recently have demonstrated at least short-term success in the management of digital mucous cysts. Cysts have been vaporized with the carbon dioxide laser and treated with infrared contact coagulation. ^{[20, 21]}

Dermatologic and plastic surgeons have practiced cold-steel surgical excision of digital mucous cysts for several decades. This procedure ranges from simple excision of the cyst to wide, radical excision with possible graft ^[22] or flap reconstruction. Flaps used for reconstruction have historically been rotation flaps, ^[23] but rhomboid flaps ^[24] as well as advancement flaps ^[25] have been used safely and reliably and may be easier to apply in selected situations.

Another approach is marsupialization, or excision of the whole proximal nail fold, with subsequent healing by secondary intention.

In recent years, excision and debridement of joint osteophytes has been recognized as a necessary adjunct to reduce the risk of recurrence. Some hand surgeons believe that excision and debridement of the marginal osteophyte without removal of the cyst itself may be the best intervention. This results in less postoperative impairment in joint motion and fewer nail deformities since cyst dissection around the germinal matrix potentially may injure the underlying matrix and cause scarring. In general, more aggressive dissection leads to fewer recurrences and more nail deformities.

More recently, nail surgeons have attempted to treat recurrent or refractory cysts by repairing the causative leak of joint fluid in such lesions. ^[26] Methylene blue dye is first injected into the distal interphalangeal (DIP) joint. Then, a skin flap is raised around the cyst to find the area of dye-filled communication between the joint space and the cyst. This communication is then sutured shut and the flap is dropped back into place without tissue resection.

Overall, significant disagreement exists in the literature regarding optimal treatment approaches.

Dermatologists tend to favor more conservative treatments such as multiple needling or aspiration followed by steroid injection; they have reported high success rates and relatively low risks of recurrence.

Hand surgeons have noted success and rare recurrence with osteophyte excision and debridement, but their patient population is comprised of those who fail other treatments. All of the literature is biased toward the minority of patients who seek medical care for their digital mucous cysts. Asymptomatic cysts and spontaneous regression appear to be common, with several series suggesting that the likelihood of the latter may approximate 50%.

Additionally, as the aggressiveness of interventions to treat digital mucous cysts increases, the associated costs also increase. Conservative treatments offer the prospect of low cost, low morbidity, and the elimination of disability and time loss related to recovery from surgery.

Consequently, a reasonable treatment plan for symptomatic digital mucous cysts may entail initial needling or aspiration and injection; if these modalities fail repeatedly, patients may be referred to a hand surgeon for more radical surgery but must be forewarned of the increased risk of complications and offered the option of simply deferring treatment for this essentially benign entity.

Consultation with a dermatologist, dermatologic surgeon, and/or hand surgeon may be warranted.

Digital mucous cysts (DMCs) have a high incidence of recurrence after treatment, typically occurring within 3 months of treatment. Sclerotherapy can result in extravasation of the sclerosant into the joint space. Short freeze-thaw cycles should predominate when cryotherapy is applied to avoid possible scarring of the nail matrix. Local depigmentation has been reported after steroid injection with triamcinolone.

Surgical interventions, while possibly slightly more effective in preventing recurrence, have many associated complications. Radial or ulnar deviation of the distal interphalangeal (DIP) joint with resulting impairment in joint motion can occur. While some nail deformities may be corrected by surgery, residual nail deformities may persist or be created de novo. Other complications include tendon injury, superficial infection, DIP septic arthritis, increased arthritic symptoms in the joint, and persistent swelling, pain, numbness, and stiffness.