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Patient Information Leaflet

Digital Myxoid Cyst

What are the aims of this leaflet?

This leaflet has been written to help you understand more about digital myxoid cysts - what they are, what causes them, what can be done about them and where you can find out more about them.

What is a digital myxoid cyst?

A digital myxoid cyst (sometimes called a mucous cyst) is an entirely benign swelling that occurs on the fingers or, sometimes, the toes. Digital myxoid cysts are not catching and not a sign of infection. Furthermore, they are not cancerous and will not develop into skin cancer.

The term cyst is from the Greek kystis meaning a bag or pouch; myxoid and mucoid refer to the jelly-like contents. Digital derives from the Latin digitus, meaning finger or toe.

Digital myxoid cysts occur most frequently in people in their sixties.

What causes a digital myxoid cyst?

The exact cause is not known. The cyst is often connected to the lining of the finger or toenail joint, and is usually located between the joint and the nail.

Is a digital myxoid cyst hereditary?

Digital myxoid cysts are not hereditary.

What are the symptoms of a digital myxoid cyst?

Although there is usually no pain, a cyst may become tender, especially when knocked. Occasionally there may also be symptoms of arthritis with pain, stiffness and deformity of the joint. Cysts often ‘get in the way’ and their appearance may cause concern. Digital myxoid cysts may become infected if they are knocked. If a cyst suddenly becomes larger, painful, red and hot, you should see your doctor as these symptoms may indicate an infection and an antibiotic may be needed.

What does a digital myxoid cyst look like?

Digital myxoid cysts are skin-coloured, reddish or slightly translucent (letting light shine through). If a cyst is overlying the area where the nail is formed, it may cause a groove to occur along the length of the nail, which can vary in width. Occasionally, slightly sticky, clear, straw-coloured or blood-stained contents may leak out of the cyst. Usually, there is just one cyst, but some people may develop more than one, on different fingers.

How is a digital myxoid cyst diagnosed?

A digital myxoid cyst is usually easily recognised as a small lump overlying the end finger- or toe-joint, with or without a groove in the adjacent fingernail. The occasional discharge of clear, slightly sticky material from the cyst is also characteristic. If the cyst arises under the nail, the diagnosis is more difficult, and then a scan or taking a sample (biopsy) from the cyst with a local anaesthetic may be needed.

Can a digital myxoid cyst be cured?

Several different treatment options exist for digital myxoid cysts, but they may come back. They may disappear spontaneously.

How can a digital myxoid cyst be treated?

If a digital myxoid cyst does not cause any symptoms, no treatment is required. If treatment is considered necessary, there are a number of options.

Treatments usually not requiring a local anaesthetic:

• Repeated drainage of the cyst fluid using a sterile needle or blade.
  
• Injection of steroids into the cyst.
  
• Freezing of the cyst with liquid nitrogen (cryotherapy).

Treatments requiring a local anaesthetic:

• Scraping the cyst off.
  
• Lifting the area of skin containing the cyst and re-attaching it. 
  
• Finding the point of leakage of fluid from the joint by injection of dye into the joint, and then closing that leak.
  
• Cutting the cyst away and applying a skin graft.
  
• Removing any rough, sharp areas on the bone caused by wear and tear from the adjacent joint.
  
• Cauterising the cyst (infrared coagulation).

Where can I get more information about digital myxoid cysts?

http://www.emedicine.com/derm/topic100.htm (includes photographs)

http://dermnetnz.org/lesions/mucous-cyst.html (includes photographs)

The British Skin Foundation fund vital research into all skin diseases. To find out how you can help, please visit the British Skin Foundation website here. 

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: its contents, however, may occasionally differ from the advice given to you by your doctor. 

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED JULY 2009