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Digital mucous cysts
Understanding digital mucous cysts, small joint-related cysts that form near the fingertip, and how they are managed.
What is a digital mucous cyst?
A digital mucous cyst is a small, fluid-filled cyst that forms near the joint closest to the fingernail (the distal interphalangeal joint, or DIPJ). It is linked to osteoarthritis in that joint, and connects to the arthritic joint through a small stalk, which allows joint fluid to leak into the cyst. The cyst usually sits just under the skin, close to the nail fold.
At a glance
What is it?
A small, fluid-filled cyst that forms near the end joint of a finger, linked to arthritis in that joint
Common symptoms
A small smooth lump near the base of the nail, sometimes with a groove in the nail
Who it affects
People with osteoarthritis of the end finger joint (whether noticeable or not), more common in older adults and women
Is it serious?
Not dangerous, but can affect nail growth or become infected if it leaks or ruptures
Treatment options
Observation or surgery
First step
A consultation to confirm the diagnosis and discuss options
Causes and risk factors
- Osteoarthritis of the end finger joint
- A bone spur at the affected joint
- More common with increasing age
- More common in women
Symptoms and how a digital mucous cyst presents
The main sign is a small, smooth lump near the base of the nail or over the end joint. It can press on the tissue that forms the nail (nail matrix) and result in a groove or ridge in the nail as it grows. The cyst can occasionally leak a clear, jelly-like fluid, and there is a risk of infection if it ruptures, because the cyst connects directly to the joint.
How is a digital mucous cyst diagnosed?
A digital mucous cyst is usually diagnosed from its appearance and location on examination. If there is uncertainty then Dr Tomlinson will refer you for an ultrasound. An x-ray may also be requested to look at the underlying joint and confirm the associated osteoarthritis.
Treatment options for digital mucous cysts
A small cyst that is not bothersome can simply be observed. Surgical excision offers a relatively reliable result for large, tender or discharging cysts. This involves removing the cyst along with its stalk and the underlying bone spur, which reduces the likelihood of it coming back.
When to see a hand surgeon
It is worth being assessed if you notice a growing or troublesome lump near your fingernail, a new groove or ridge in the nail, or if a cyst has ruptured or shows signs of infection such as redness, pain or discharge.
What to expect at your appointment
At your appointment, Dr Tomlinson will examine the lump and the finger. If there is uncertainty about the diagnosis she will refer you for an ultrasound, and may also request an x-ray. Together you will discuss whether observation or surgical removal is the right option for you.
Watch: Understanding Digital Mucous Cysts
Frequently Asked Questions
What is a digital mucous cyst?
A small, fluid-filled cyst that forms near the joint closest to the fingernail, linked to osteoarthritis in that joint, connecting to the joint through a small stalk that allows joint fluid to leak into the cyst.
What causes it?
Digital mucous cysts are associated with osteoarthritis of the end finger joint, a bone spur at the affected joint, increasing age, and being female.
What can I do myself?
A small cyst that isn’t bothersome can simply be observed. It’s worth being assessed if you notice a growing or troublesome lump, a new groove or ridge in the nail, or if a cyst has ruptured or shows signs of infection.
What can a hand therapist do?
Digital mucous cysts are not typically managed by a hand therapist, though a hand therapist can support your recovery with therapy if you have surgery.
What can a hand surgeon do?
Confirm the diagnosis on examination, arranging an ultrasound or x-ray if there is uncertainty. For large, tender or discharging cysts, surgical excision removes the cyst along with its stalk and the underlying bone spur, which reduces the likelihood of it coming back.
What can I expect from treatment?
A small, non-bothersome cyst can simply be watched. Surgical excision offers a relatively reliable result for troublesome cysts, removing the cyst and its connection to the joint.
What happens if it's left untreated?
The cyst can continue to press on the nail matrix, affecting nail growth, and there is a risk of infection if it leaks or ruptures, since it connects directly to the joint.
Related conditions and treatments
Digital mucous cysts are closely linked to finger osteoarthritis at the affected joint. They are a specific type of ganglion cyst, distinguished by their location and connection to an arthritic joint.