Ganglion cysts and common lumps explained

What a ganglion cyst is

A ganglion cyst is a smooth, fluid-filled lump that usually appears around a joint or tendon, most often on the back of the wrist, but also on the front of the wrist, the fingers or the top of the foot. It forms when the thick, jelly-like fluid that lubricates a joint or tendon sheath collects in a small balloon of tissue. Ganglions are completely harmless — they are not cancer and cannot become cancer. They can vary in size, sometimes growing or shrinking over weeks, and they may be firm or slightly springy. Some cause no trouble at all; others ache or get in the way, especially if they press on a nearby nerve or sit where you lean or grip.

Other common harmless lumps

Several other everyday lumps are frequently mistaken for something worrying. A lipoma is a soft, movable lump of fatty tissue under the skin — painless, slow-growing and harmless. A skin (epidermoid or sebaceous) cyst is a small sac under the skin filled with a cheesy material; it can sometimes become red and sore if it gets inflamed or infected. Swollen lymph glands in the neck, armpit or groin often appear during infections and settle afterwards. Skin tags, warts and enlarged oil glands are all common and benign. Knowing that these ordinary lumps exist — soft, movable, slow-changing and painless — helps put a new bump in perspective, though any lump you are unsure about is worth having checked.

Do lumps need treatment?

Most harmless lumps need no treatment at all. Many ganglion cysts disappear on their own over months or years, so if one is not causing problems, leaving it alone is a perfectly reasonable choice — sometimes called "watchful waiting". The old folk remedy of hitting a ganglion with a heavy book is not recommended, as it can cause injury and the cyst often returns. If a ganglion is painful or limiting movement, options include draining the fluid with a needle, though it commonly comes back, or surgery to remove it, which has a better chance of a lasting result but is usually reserved for troublesome cysts. Lipomas and skin cysts are generally only removed if they are painful, growing or bothersome.

When a lump needs checking

While most lumps are harmless, some features should prompt a prompt visit to your GP. Be checked if a lump is growing quickly, is hard and does not move freely under the skin, feels fixed to deeper tissues, or is painful without obvious reason. A lump that appears after a change in a mole, or is accompanied by unexplained weight loss, night sweats, fever or feeling generally unwell, also needs assessment. Any new lump in the breast or testicle should always be checked, and a lymph gland that stays enlarged for more than a few weeks without an infection should be reviewed. Getting a lump examined is straightforward, and being checked brings reassurance far more often than bad news.

What to expect at the GP

Assessing a lump is usually quick and simple. Your GP will ask how long it has been there, whether it has changed, and if it hurts, then examine it — feeling its size, texture, whether it moves, and looking at the overlying skin. Many lumps, such as a classic wrist ganglion or a soft lipoma, can be confidently identified from the examination alone. If there is any uncertainty, the GP may arrange a scan such as an ultrasound, or refer you to a specialist for a closer look or a small sample (biopsy). Shining a light through a wrist ganglion, which glows because it is fluid-filled, is a simple clue clinicians sometimes use. The key message is that checking is easy and worthwhile.