A ganglion cyst is a fluid-filled sac that grows out of a joint or tendon sheath. On the foot it usually appears on the top, over the midfoot, or along a tendon — a smooth, slightly mobile lump that patients discover while putting on a shoe. Most are harmless. Some hurt, some press on a nerve, and a few are not ganglia at all.
We identify it before we drain it.
The cyst is a balloon of thick, jelly-like fluid leaking from a joint capsule or tendon lining. It can change size from week to week. On the foot, common sites are the dorsal midfoot (often over an arthritic joint — see arthritic foot), the ankle, and the inside ankle where a cyst can contribute to tarsal tunnel.
It is not Ledderhose disease (a firm plantar fibroma) and it is not a bone spur, though a spur can sit underneath.
We transilluminate, feel whether it is fixed to bone, and usually confirm with ultrasound. If anything about the mass is atypical — solid, rapidly growing, oddly pigmented, or in an unusual place — we image further or biopsy. “Drain first, think later” is how other things get missed.
A painless, typical ganglion that is not growing can be observed.
We can drain the fluid in the office. Recurrence is common because the root is still there. It is a reasonable first step when the cyst is painful or shoe-limiting and looks classic on ultrasound.
If midfoot arthritis is feeding the cyst, orthotics and the arthritis plan matter more than the syringe.
Surgical removal, including the stalk, is for cysts that recur, press on a nerve, or sit where we cannot safely aspirate. Dr. Shalot performs that when it is indicated.
Aspiration is a same-day walk-out. After excision, expect a short period of limited activity while the soft tissue seals. Recurrence can still happen; we say that before we start.
Evaluation with ultrasound typically $200–$500. Aspiration is often in the $250–$600 range. Excision is a surgical fee. Insurance frequently applies when the cyst is symptomatic.
No. That folklore belongs in a museum.
It might. That is why we talk about the joint underneath.
Almost all of these are benign. The unusual ones get imaged and, if needed, sampled — we do not wave that away.
