Medically reviewed by Dr. A.M. van Coevorden, dermatologist, on
DermatofibromaHard, benign bump in the skin
A dermatofibroma (histiocytoma) is a slow-growing, firm bump in the skin, usually on the lower legs. It is benign, does not go away on its own and usually does not need treatment.
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- What is a dermatofibroma?
- What causes a dermatofibroma?
- Hard lump in the skin: what does a dermatofibroma look like?
- How does the dermatologist make the diagnosis?
- Dermatofibroma removal: is it necessary?
- Does a dermatofibroma go away on its own?
- Dermatofibroma: what you can do yourself
- When to see a dermatologist or GP?
- Frequently asked questions about dermatofibroma
What is a dermatofibroma?
A dermatofibroma is a benign bump of connective tissue in the skin. It feels like a hard disc or ball that is attached to the skin but can be moved over the tissue underneath. Doctors also call it a histiocytoma or benign fibrous histiocytoma.
Dermatofibromas are common in adults between twenty and fifty, more often in women than in men. Usually you have one, sometimes a few. The lower legs are the most common site, followed by the arms.
A dermatofibroma is not contagious and is not skin cancer. It is a benign thickening of connective tissue.
What causes a dermatofibroma?
The cause is not known. It may be a slightly exaggerated scar reaction after a minor skin injury, such as an insect bite or an inflamed hair follicle. This has never been proven.
Several dermatofibromas at the same time are sometimes seen in people with a weakened immune system or an autoimmune disease.
Hard lump in the skin: what does a dermatofibroma look like?
A dermatofibroma is a firm to hard bump of about half a centimetre to one and a half centimetres. It often sits slightly sunken in the skin, sometimes it is dome-shaped. The colour varies: skin-coloured, pink, red, brown or grey.
- Hard, small bump that is attached to the skin.
- Usually on the lower legs, sometimes on the arms or trunk.
- Skin-coloured to brown, sometimes darker at the edge.
- Grows very slowly or stays the same for years.
- Few symptoms, sometimes itching or tenderness.
A characteristic feature is the dimple sign: when you pinch the skin around the bump between thumb and index finger, the bump does not rise but a dimple appears. A hard lump in the skin can fit a dermatofibroma, but also other spots. The dermatologist makes the distinction.
How does the dermatologist make the diagnosis?
The dermatologist usually recognises a dermatofibroma by its appearance: the colour, the hard consistency, the dimple sign, the location on the leg and the fact that it has been there for a long time and hardly changes. With a dermatoscope the dermatologist sees characteristic patterns.
If in doubt, the bump is cut out and examined in the laboratory. This matters, because a dermatofibroma can sometimes resemble a mole, a basal cell carcinoma or, in rare cases, a melanoma.
With 247dermatologist you upload photos of the bump and answer a few questions. A registered dermatologist assesses them within 12 to 48 hours.
Dermatofibroma removal: is it necessary?
The usual advice is not to treat a dermatofibroma. It is benign and rarely causes symptoms. Removal is an option if the bump hurts, itches, keeps getting knocked or if the diagnosis is uncertain.
Watch and wait
The standard approach. The bump stays, but it is harmless. Keep an eye on it for changes.
Surgical removal
The bump is cut out under local anaesthetic and sent for examination. This is done at a dermatology or GP practice, not online.
Know what you are choosing
Because a dermatofibroma sits deep in the skin, it leaves a scar that is often larger and less attractive than the bump itself. If it is not completely removed, it often comes back.
Does a dermatofibroma go away on its own?
No. A dermatofibroma does not disappear by itself, but it does not grow larger than about one and a half centimetres and stays benign. The outlook is good. After complete removal it usually does not come back.
Dermatofibroma: what you can do yourself
- Leave the bump alone if it causes no symptoms.
- Do not try to squeeze it out or cut it off yourself.
- Protect it from knocks when shaving or playing sport.
- Watch for changes: rapid growth, darkening, bleeding or a sore that does not heal.
When to see a dermatologist or GP?
Have the bump assessed if:
- You are not sure whether the hard lump is a dermatofibroma.
- The bump grows quickly, changes colour or becomes irregular.
- It bleeds, hurts or does not heal after a knock.
- You develop several new bumps in a short time.
A dermatologist at 247dermatologist assesses your photos and tells you whether the picture fits a dermatofibroma and whether further investigation is needed. No referral needed.
Frequently asked questions about dermatofibroma
Not sure whether this needs a look? Have a dermatologist assess it: you get an answer within 12 to 48 hours, no referral needed. In an emergency, contact your GP straight away or call 112.
Is a dermatofibroma dangerous?
No. A dermatofibroma is benign and does not turn into skin cancer. Only if a bump grows quickly, changes colour or bleeds is investigation needed to rule out other spots.
How do I know if a hard lump is a dermatofibroma?
Typical is a small, hard, fixed bump on the lower leg that stays the same for years and dimples when you pinch the skin around it. You can only be sure after assessment by a doctor.
Does a dermatofibroma need to be removed?
Usually not. Removal is only worthwhile if it causes symptoms or if the diagnosis is uncertain. The scar is often larger than the bump.
Does a dermatofibroma come back after removal?
If it has been completely cut out, usually not. If part of it remains, it often grows back.
Can you have several dermatofibromas?
Yes. Usually you have one or a few. Many dermatofibromas at once is rare and is sometimes seen with a weakened immune system.
What is the difference between a dermatofibroma and a lipoma?
A lipoma is a soft, larger fatty lump under the skin that you can move around. A dermatofibroma is small and hard and is attached to the skin.
Have a dermatologist look at your skin
Upload photos and answer a few questions. A BIG-registered dermatologist replies within 12 to 48 hours, no referral needed, from € 39.
If more is needed, the dermatologist refers you to a medical specialist.
Want to know what a dermatologist does, when you can see one and how quickly that can happen? Read more about the dermatologist.
Sources and more information
- Huidziekten.nl, patiëntenfolder Dermatofibroom
- Huidinfo.nl, Dermatofibroom
- Huidziekten.nl, zakboek Dermatofibroom (benigne fibreus histiocytoom)
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