Fibroadenoma

A fibroadenoma is a very common benign (not cancer) breast condition. The most common symptom is a lump in the breast which usually moves when you touch it.

Fibroadenomas often develop during puberty so are mostly found in young women, but they can occur in women of any age. Men can also get fibroadenomas, but this is very rare.    

Symptoms of fibroadenoma

A fibroadenoma is usually felt as a lump in the breast which has a rubbery texture, is smooth to the touch and moves easily under the skin.

Fibroadenomas are usually painless, but sometimes they may feel tender or even painful, particularly just before a period.

Types of fibroadenoma

Simple fibroadenoma

Most fibroadenomas are about 1–3cm in size and are called simple fibroadenomas. When looked at under a microscope, simple fibroadenomas will look the same all over.

Simple fibroadenomas don’t increase the risk of developing breast cancer in the future.

Complex fibroadenoma

Some fibroadenomas are called complex fibroadenomas. When these are looked at under a microscope, some of the cells have different features.

Having a complex fibroadenoma can very slightly increase the risk of developing breast cancer in the future.

Giant or juvenile fibroadenoma

Occasionally, a fibroadenoma can grow to more than 5cm and may be called a giant fibroadenoma. Those found in teenage girls may be called juvenile fibroadenomas.

Causes

It’s not known what causes a fibroadenoma. It’s thought that it probably occurs because of increased sensitivity to the hormone oestrogen. 

Breasts are made up of lobules (milk-producing glands) and ducts (tubes that carry milk to the nipple). These are surrounded by glandular, fibrous and fatty tissue.

Fibroadenomas develop from a lobule. The glandular tissue and ducts grow over the lobule and form a solid lump.

breast diagram illustration checking

Diagnosis

If you find a breast lump, see your GP (local doctor). They’re likely to refer you to a breast clinic where you’ll be seen by specialist doctors or nurses.

At the breast clinic you’ll have various investigations, known as ‘triple assessment’, to help make a definite diagnosis. This assessment consists of:

Fibroadenomas are often easier to identify in younger women. If you’re in your early 20s or younger, your fibroadenoma may be diagnosed with a breast examination and ultrasound only. However, if there’s any uncertainty about the diagnosis, a core biopsy or FNA will be done.

If you’re under 40, you’re more likely to have an ultrasound than a mammogram. Younger women’s breast tissue can be dense which can make the x-ray image less clear so normal changes or benign breast conditions can be harder to identify. However, for some women under 40, mammograms may still be needed to complete the assessment.

Follow-up or treatment

In most cases you won’t need any follow-up or treatment if you have a fibroadenoma. Usually you’ll only be asked to go back to your GP or the breast clinic if it gets bigger or you notice a change.

Most fibroadenomas stay the same size. Some get smaller and some eventually disappear over time. A small number of fibroadenomas get bigger, particularly those in teenage girls. Fibroadenomas can also get bigger during pregnancy and breastfeeding or while taking hormone replacement therapy (HRT), but usually reduce in size again afterwards.

Surgery

Sometimes an operation called an excision biopsy is needed to remove a fibroadenoma if it’s a large, complex or juvenile fibroadenoma. You can also ask to have a fibroadenoma removed.

This may be done using a local or general anaesthetic.

Your surgeon may use dissolvable stitches placed under the skin which won’t need to be removed. However, if a non-dissolvable type is used, they will need to be taken out a few days after surgery. You’ll be given information about this and about looking after the wound before you leave the hospital.

Vacuum assisted excision biopsy

You may be offered a vacuum assisted excision biopsy to remove the fibroadenoma. This is a way of removing small fibroadenomas under local anaesthetic, without having surgery.

After an injection of local anaesthetic, a small cut is made in the skin. A hollow probe connected to a vacuum device is placed through this. Using an ultrasound or mammogram as a guide, the fibroadenoma is sucked through the probe by the vacuum into a collecting chamber. The biopsy device is used in this way until all of the fibroadenoma has been removed. This may mean that an operation under a general anaesthetic can be avoided. The tissue removed is sent to a laboratory and examined under a microscope. This procedure can cause some bruising and pain for a few days afterwards.

Removing a fibroadenoma doesn’t usually affect the shape of the breast, but there may be a slight dent in the breast where it has been removed.

Staying breast aware

For most women, having a fibroadenoma does not increase the risk of developing breast cancer.

If you were diagnosed with a complex fibroadenoma, you may be worried that your risk is very slightly increased. However, this doesn’t necessarily mean you will develop breast cancer in the future.

It’s important to continue to be breast aware and go back to your GP if you notice any changes in your breasts, regardless of how soon these occur after your diagnosis of a fibroadenoma.

Last reviewed: June 2016
Next planned review begins 2018

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