What Is a Ganglion Cyst?

A ganglion cyst is a fluid-filled sac that develops adjacent to a joint capsule or tendon sheath. The fluid inside is thick, gelatinous synovial fluid similar to the lubricating fluid within joints. Ganglion cysts are benign — they are not cancerous and do not spread — but they can cause pain, pressure, and cosmetic concern depending on their location and size.

In the foot and ankle, ganglion cysts most commonly develop on the dorsum (top) of the foot near the second and third tarsometatarsal joints, around the ankle joint, along tendon sheaths of the peroneal tendons or tibialis tendons, and near the first MTP joint. The top-of-foot location is particularly common and often becomes symptomatic from direct shoe pressure.

What Causes Ganglion Cysts?

The exact mechanism of ganglion cyst formation is not fully understood. The prevailing theory involves a defect or irritation in the joint capsule or tendon sheath, through which joint fluid is forced under pressure, creating the cystic structure. Repetitive stress, minor trauma, and joint degeneration are associated contributing factors. Many ganglions develop without any clear precipitating event.

Ganglion cysts are the most common soft tissue tumors of the hand and wrist, and are the second most common in the foot (after plantar fibromas). They are more common in women and in patients aged 20–40, though they occur at any age.

Symptoms

Many ganglion cysts are asymptomatic — discovered incidentally or noticed as a cosmetic lump. Symptomatic cysts cause:

• Aching pain over the cyst, particularly with activity
• Direct pressure pain from shoe contact (especially dorsal foot cysts)
• Tingling or numbness if the cyst compresses adjacent nerves
• Restricted joint movement if the cyst is large or near a joint

Cysts may fluctuate in size — sometimes shrinking with rest and enlarging with activity as pressure within the joint fluctuates. Some cysts spontaneously resolve without any treatment.

Diagnosis

Clinical examination is usually sufficient — a soft, transilluminable (light passes through it) cystic mass near a joint or tendon is characteristic. Ultrasound confirms the cystic nature, identifies the stalk connecting the cyst to the underlying structure, and guides aspiration if indicated. MRI provides the most detailed assessment and is useful for deeper or atypical cysts.

Treatment Options

Observation

For asymptomatic or minimally symptomatic cysts, observation with periodic monitoring is appropriate — many cysts resolve spontaneously. Shoe modification (wider toe box, lower vamp) can reduce pressure over dorsal cysts without any procedural intervention.

Aspiration

Aspiration (draining the cyst with a needle and syringe) can be performed in the office under ultrasound guidance. The thick gelatinous fluid is removed, and the cyst collapses. Recurrence rates after aspiration range from 30–50%, as the underlying stalk connecting the cyst to the joint remains intact. Some clinicians inject corticosteroid after aspiration to reduce recurrence risk, with modest evidence of benefit.

Surgical Excision

Surgical excision removes the cyst and its stalk (the connection to the underlying joint or tendon sheath) through a small incision. This provides the lowest recurrence rate — approximately 5–15% — and is preferred for symptomatic cysts that have failed aspiration or are too deep for reliable aspiration. The procedure is performed under local or regional anesthesia as a brief outpatient procedure with rapid recovery.

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Dr. Tom Biernacki, DPM

Dr. Tom Biernacki, DPM is a double board-certified podiatrist and foot & ankle surgeon at Balance Foot & Ankle Specialists in Southeast Michigan. With over a decade of clinical experience, he specializes in heel pain, bunions, diabetic foot care, sports injuries, and minimally invasive surgery. Dr. Biernacki is a member of the APMA and ACFAS, and his patient education content on MichiganFootDoctors.com and YouTube has reached over one million views.