Dermatofibromas are small, harmless growths that appear on the skin. These growths, or papules, can develop anywhere on the body, but they are most common on the arms, lower legs, and upper back.

Dermatofibromas tend to form on the skin of the arms or legs.Share on Pinterest
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Dermatofibromas most commonly occur in adults and can affect people of any ethnicity. They are more prevalent among females than males and more common in people with a compromised immune system.

Keep reading to learn more about dermatofibromas, including the symptoms and treatment options.

Dermatofibromas are harmless growths within the skin that usually have a small diameter. They can vary in color but are typically pink to light brown in light skin and dark brown or black in dark skin. They may appear more pink or darker if a person accidentally irritates them — for example, when shaving.

As they are dense and firm to the touch, many people say that they feel like a small stone underneath or raised above the skin. Most dermatofibromas are painless, but some people experience itching, irritation, or tenderness at the site of the growth.

Some doctors or medical researchers may refer to dermatofibromas as benign fibrous histiocytomas.

A dermatofibroma is a nodule made of fibrous tissue. When a doctor squeezes the nodule during an examination, the overlying skin dimples. © DermNet New Zealand  Share on Pinterest
A dermatofibroma is a nodule made of fibrous tissue. When a doctor squeezes the nodule during an examination, the overlying skin dimples. © DermNet New Zealand

Dermatofibromas are an accumulation of extra cells within the deeper layers of the skin. Medical researchers do not know the exact cause of these growths.

Some researchers theorize that a possible cause is an adverse reaction to a local trauma, such as a small injury or bug bite in the area where the lesion later forms.

Age may be another risk factor, as the growths appear mostly in adults. People with a suppressed immune system may also be more likely to experience dermatofibromas and to have more than one growth.

Multiple dermatofibromas are also more common in people with underlying conditions, especially in those with systemic lupus erythematosus. In some cases, there may not be an obvious cause.

Dermatofibromas tend to grow slowly. The growths typically have some defining characteristics that can aid their identification.

Key markers of a dermatofibroma are:

  • Appearance: A dermatofibroma presents as a round bump that is mostly under the skin.
  • Size: The normal range is about 0.5–1.5 centimeters (cm), with most lesions being 0.7–1.0 cm in diameter. The size will usually remain stable.
  • Color: The growths vary in color among individuals but will generally be pink, red, gray, brown, or black.
  • Location: Dermatofibromas are most common on the legs, but they sometimes appear on the arms, trunk, and, less commonly, elsewhere on the body.
  • Additional symptoms: Although they are usually harmless and painless, these growths may occasionally be itchy, tender, painful, or inflamed.

If a person pinches a dermatofibroma, it will not push toward the surface of the skin. Instead, it will dimple inward on itself. This characteristic can help people distinguish between a dermatofibroma and another type of growth.

It is common for only one growth to appear on the body, but multiple dermatofibromas may occur in people with underlying health conditions or a weakened immune system.

Skin growths can be alarming, but dermatofibromas are generally harmless.

However, if a person has a growth that looks like a dermatofibroma but is rapidly growing or changing, they should seek medical advice. This growth may be a sign of a rare type of cancer called dermatofibrosarcoma protuberans.

Primary care doctors and dermatologists will usually diagnose a dermatofibroma by inspecting it visually. The papules are easy to identify, but doctors will also want to be certain that they do not misdiagnose the growth.

In addition to asking a person questions about their symptoms and examining the area, a doctor is likely to perform the following:

  • Pinch test: The doctor may pinch the surrounding skin to check for the characteristic dimple.
  • Dermatoscope: The doctor may use this device to take a magnified look at the surface of the growth. Dermatofibromas will usually have a central white area in the middle with a pigmented area surrounding it.
  • Biopsy: If the growth is bleeding, abnormally shaped, or irritated, or it has a sore on top of it, doctors may want to do a biopsy. This procedure involves taking a small bit of the tissue from the papule to examine under a microscope in a laboratory.

A doctor may wish to rule out conditions that can look similar to dermatofibromas. Some of the possible diagnoses for growths that may, in rare cases, resemble dermatofibromas are:

  • hypertrophic scarring or keloid
  • malignant melanoma
  • squamous cell carcinoma
  • basal cell carcinoma
  • Spitz nevus
  • blue nevus

A rare skin cancer called dermatofibrosarcoma protuberans also initially resembles a dermatofibroma.

Due to this, a qualified doctor should always make the diagnosis.

Most dermatofibromas do not require treatment. A person can safely leave them alone, and they will usually cause no symptoms aside from their appearance on the skin.

Dermatofibroma removal

Removal is typically the simplest and most successful option, but it requires a surgical procedure. People may request this treatment if they have a growth that is unsightly or in an embarrassing place. However, the surgery may leave noticeable scar tissue after the area heals.

For this reason, doctors do not generally advise removal unless the growth is painful.

Dermatofibromas comprise a mixture of tissues, including blood vessels, fibroblasts, and macrophages. The growths run into the dermis, which is the middle layer of the skin. In rare cases, the growths can extend to the subcutis, which is deeper. These types of growths may be harder to remove surgically.

Other treatment options

Other treatment methods include freezing the growth with liquid nitrogen, injecting it with corticosteroids, or using laser procedures.

However, these methods may not be effective.

There are currently no known methods of permanently changing the size of a dermatofibroma. Occasionally, a growth may shrink or disappear on its own, but this is rare.

A person should not try to remove these growths at home. Improper removal can lead to deep scarring, infection, and improper healing.

Dermatofibromas are harmless growths that develop on the skin. However, they will not usually go away on their own.

A person can opt for the surgical removal of unsightly or uncomfortable growths, or they can try a variety of other, less invasive treatments. However, these other treatments may not remove the entire growth.

Even though dermatofibromas are benign, a person should report any new skin growth to a doctor, especially if it is changing in size, shape, or color and has an irregular pattern.

A person should also report any growth that bleeds, becomes painful, itches, or grows rapidly as soon as possible. In some cases, such growths may indicate similar but more serious skin conditions. Consulting a doctor is the best way to ensure an accurate diagnosis and an effective treatment plan.