A lipoma is a benign fatty tumour that grows slowly under the skin — soft, mobile and painless. It is very common and almost always harmless. It does not necessarily need removing; we advise it when the lipoma is bothersome, growing, or in doubt. Be cautious with a lump that is growing quickly, painful, or hard/fixed: these need checking.
"Doctor, I found a lump — could it be something serious?" It is one of the most common worries, and fortunately the answer is usually reassuring: most lumps under the skin are lipomas — harmless collections of fat. The goal is to know when a lump falls outside the "typical" picture and deserves a closer look.
What a lipoma is
A lipoma is a benign tumour made of fat cells — essentially a "capsule" of fat forming in the layer beneath the skin. It grows slowly, may stay stable for years, and appears most often on the shoulders, neck, back, arms and thighs. There may be one or several.
How to recognise it — and how it differs
A typical lipoma has a characteristic "feel" on examination:
- Soft and rubbery, like dough.
- Mobile — it "slips" under your fingers when you press it.
- Painless in most cases.
- With normal skin over it, no pore or colour change.
These features also help distinguish it from other lesions — for example from moles and superficial skin lesions, which sit within the skin rather than beneath it.
Is it dangerous?
In the vast majority of cases, no. A lipoma is benign and does not turn into cancer. Its importance lies not in the lipoma itself but in not confusing it with the rare cases where a soft-tissue lump hides something different — which is why the warning signs exist.
When it needs checking: the warning signs
Seek assessment — and probably imaging — when a lump shows any of the following:
- Rapid growth in size.
- Pain or tenderness.
- It is hard, fixed or does not move.
- It is large (bigger than ~5 cm).
- It lies deep, within or beneath the muscles.
When removal is advised
A typical, small, symptom-free lipoma can simply be monitored. Removal is advised when it:
- Is mechanically bothersome: presses, hurts or rubs on clothing.
- Is growing or changing character.
- For cosmetic reasons.
- There is diagnostic uncertainty and we want a definite diagnosis.
How removal is done
Most lipomas are removed with a simple minor procedure under local anaesthesia: a small incision, removal of the whole fatty "capsule", and closure with stitches. It takes a short time and is done as an outpatient. The specimen is sent for histological examination for a definite diagnosis. Large or deep lipomas may need a more extensive operation, after imaging.
When to see a doctor
Show the lump to a doctor if you have any doubt — and without delay if it grows quickly, hurts, or is hard or fixed. A brief clinical examination, with or without an ultrasound, is usually enough to clarify the picture.
What is a lipoma, and is it dangerous?
A lipoma is a benign tumour of fat cells that grows slowly under the skin. It is very common and almost always harmless — it does not turn into cancer. However, any lump that grows quickly, is painful, or is hard and fixed should be assessed by a doctor.
How do I tell a lipoma from a cyst?
A lipoma is usually soft and mobile it 'slips' under the fingers, sits deeper, and has no surface pore. A sebaceous cyst often has a small pore on the skin and can become inflamed or infected. The definitive distinction is made clinically and, if needed, with an ultrasound.
When should a lump be checked?
When it grows quickly, is painful, is hard or fixed (does not move), is larger than about 5 cm, or lies deep within the muscles. In these cases imaging (ultrasound or MRI) is needed to rule out something other than a simple lipoma.
Does a lipoma always need removing?
No. A typical, small, symptom-free lipoma can simply be monitored. Removal is advised when it is bothersome (presses, hurts, rubs), when it is growing, for cosmetic reasons, or when there is diagnostic uncertainty.
How is it removed, and will there be a scar?
Most lipomas are removed with a minor procedure under local anaesthesia, through a small incision, and are sent for histological examination. The scar is usually small; the size and location of the lipoma determine the final result. Large or deep lipomas may need a more extensive operation.