What is a fibroadenoma?
Breasts are made up of lobules (milk-producing glands) and ducts (tubes that carry milk to the nipple), which are surrounded by glandular, fibrous and fatty tissue. Fibroadenomas develop from a lobule. The glandular tissue and ducts grow over the lobule, forming a lump.
Fibroadenomas are benign (not cancer) and don’t increase the risk of developing breast cancer. They are thought to occur because of an increased sensitivity to the female hormone oestrogen.
A fibroadenoma usually has a smooth rubbery texture and can move easily under the skin. Fibroadenomas are usually painless, but some people may feel some tenderness or even pain.
Fibroadenomas are very common and it is not unusual to have more than one. Often developing during puberty, they are mostly found in young women, but can occur at any age.
Most fibroadenomas are about 1 to 3cm in size. When more than 5cm they’re called giant fibroadenomas. Fibroadenomas found in teenage girls are called juvenile fibroadenomas. They may also be giant fibroadenomas.
Most fibroadenomas stay the same size. Some get smaller and some eventually disappear over time. Infrequently, fibroadenomas get bigger, particularly in teenage girls and pregnant and breastfeeding women, but often get smaller again. This is quite normal and nothing to worry about.
How are they diagnosed?
Fibroadenomas usually become noticeable as a lump in the breast. Your GP will note the lump and refer you to a breast clinic for testing.
Three tests (a triple assessment) should provide a definite diagnosis. These are:
- a breast examination
- a mammogram (breast x-ray) or ultrasound scan
- a fine needle aspiration (FNA) or core biopsy.
If you are younger than 40 you’re more likely to have an ultrasound scan rather than a mammogram. This is because younger women’s breast tissue is often too dense to give a clear mammogram image.
Fibroadenomas are often easier to identify in women under 25. If you are in this age group, your fibroadenoma may be diagnosed by examination and ultrasound only. However, if there is any uncertainty, an FNA or core biopsy can be done.
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 becomes painful.
Sometimes large fibroadenomas may need to be removed in a small operation called an excision biopsy. You can also request to have it removed if you would prefer. The operation will leave a small scar, which will fade in time.
Removing a fibroadenoma doesn’t usually affect the shape of the breast, as normal breast tissue will fill the space where it used to be.
You may be offered a vacuum assisted excision biopsy to remove a small fibrodenoma.
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 ultrasound or mammography as a guide, breast tissue is sucked through the probe by the vacuum into a collecting chamber. The biopsy device is used until the area being investigated has been removed. This may mean that an operation under a general anaesthetic can be avoided. The tissue removed is sent to the laboratory and examined under a microscope.
Last reviewed March 2012; next planned review 2014