Fibroma: Types, Causes and Treatment

What a fibroma is

Connective tissue holds the body together. Its main cells, fibroblasts, make collagen. A fibroma forms when fibroblasts multiply locally and lay down extra collagen, producing a firm, rubbery or soft lump. Causes vary by type: minor injury and irritation are the commonest triggers, and some forms run in families or come with genetic syndromes.

The word is used loosely. "Fibroids" of the uterus are actually smooth-muscle tumors (leiomyomas), and a breast "fibroadenoma" contains glandular as well as fibrous tissue. Both are benign, but they are separate conditions with their own pages: uterine fibroids and fibroadenoma.

Types of fibroma

Symptoms

Most fibromas cause no symptoms beyond the lump. Possible problems depend on location:

• Skin: itching, catching on clothes or razors, or bleeding if nicked.
• Mouth: being bitten repeatedly, which makes the lump larger.
• Foot: pain with walking or tight shoes.
• Bone: a large nonossifying fibroma can weaken bone and cause a fracture after minor injury.
• Ovary: pelvic pressure or pain. A large ovarian fibroma can occasionally cause fluid in the abdomen and chest (Meigs syndrome), which goes away after removal.

Fibroma or something more serious?

Most lumps under the skin are harmless (lipomas, cysts, fibromas). Features that call for prompt imaging or biopsy to exclude a soft tissue sarcoma are:

• Size over 5 cm.
• Steady growth.
• Deep location, under the muscle layer or fixed to it.
• New pain in the lump.
• Return after previous removal.

A changing pigmented skin lesion needs checking to rule out melanoma, and some rare skin tumors (dermatofibrosarcoma protuberans) can look like a large or growing dermatofibroma.

Diagnosis

• Examination: many skin and mouth fibromas are recognized on sight. The "dimple sign" points strongly to a dermatofibroma.
• Dermoscopy for skin lesions.
• Ultrasound or MRI for deeper lumps such as plantar fibromas, tendon sheath lumps and ovarian masses.
• X-ray for bone lesions. Nonossifying fibromas have a classic bubbly look at the end of a long bone.
• Biopsy: a small sample or full removal sent to the lab, when the diagnosis is uncertain.

Treatment

Treatment depends on the type and on whether the lump causes problems.

• Observation for small stable skin fibromas and most nonossifying fibromas in children, which fill in with bone as the child grows.
• Surgical excision: removes the whole lump and gives a definite diagnosis. Expect a scar, which can be larger than the original lump on the legs.
• Snip, freezing or cautery: for skin tags, done quickly in a clinic.
• Simple excision in the mouth: for an irritation fibroma, along with fixing the cause, such as a sharp tooth or ill-fitting denture.
• Plantar fibromas: padded insoles and supportive shoes first, steroid injections for pain, and surgery only when walking is affected, because recurrence after surgery is common.
• Ovarian fibroma: surgical removal, usually by keyhole surgery, which also confirms it is benign.
• Bone: large lesions at risk of fracture may be scraped out and filled with bone graft.

Do not try to cut off a skin lesion at home. It can bleed, become infected and leave a diagnosis unconfirmed.

Outlook

Fibromas are benign and do not spread. Skin and oral fibromas usually stay the same size for years. Some return after removal, especially plantar fibromas. People with many fibromas, or fibromas appearing at a young age, may be checked for an associated genetic syndrome.

Frequently asked questions

What is a fibroma?

A fibroma is a benign lump made mostly of fibrous connective tissue, the collagen-rich tissue found in scars and tendons. Fibromas can form in the skin, mouth, foot, bone, ovary and elsewhere. They are not cancer and do not spread, although a doctor may need to examine a lump to confirm it.

Is a fibroma cancerous?

No. A true fibroma is benign. However, some cancers, such as soft tissue sarcoma or a rare skin cancer called dermatofibrosarcoma protuberans, can look similar. Lumps that are large, growing, deep or painful should be checked, and a biopsy may be needed to be sure.

What causes a fibroma?

Many fibromas follow minor injury or chronic irritation, such as an insect bite (dermatofibroma) or repeated cheek biting (oral fibroma). Others relate to friction in skin folds, hormones, or genetic conditions such as tuberous sclerosis. Often there is no clear cause.

Should a fibroma be removed?

Not always. Removal is reasonable if the lump hurts, catches on clothing or teeth, bleeds, affects walking, is growing, or the diagnosis is uncertain. Small, stable, symptom-free fibromas can simply be watched. Surgical removal leaves a scar, which is worth weighing for cosmetic reasons.

What does an oral fibroma look like?

An oral irritation fibroma is a smooth, firm, pink dome inside the cheek, on the lip or on the side of the tongue, usually where teeth rub or you bite. It is painless unless bitten. A dentist can remove it, but any mouth lump or sore lasting more than 3 weeks should be checked.