Fibroadenoma of the Breast

What is a fibroadenoma?

Fibroadenomas grow from a breast lobule, the milk-producing unit, when the gland cells and the surrounding supportive (stromal) tissue overgrow together. They are sensitive to the hormones estrogen and progesterone. That is why they appear in the teens and twenties, can enlarge during pregnancy, breastfeeding or hormone therapy, and often shrink after menopause.

Around 1 in 10 women will have a fibroadenoma at some point. About 10 to 15% of women with one have more than one, sometimes in both breasts.

Types of fibroadenoma

A phyllodes tumor can look like a fibroadenoma on a scan but behaves differently: it grows faster and can recur. A biopsy and sometimes removal are needed to tell them apart. See phyllodes tumor.

Symptoms

• A single painless breast lump that is round, smooth and well defined
• Firm or rubbery feel, like a marble or a grape
• Moves easily under the fingers
• Usually stays the same size, though it may get slightly bigger or tender before a period or in pregnancy

Many fibroadenomas are found by chance on a scan, with no symptoms at all.

Fibroadenoma vs breast cyst vs cancer

No one can tell these apart reliably by touch alone, so any new lump needs imaging.

How fibroadenoma is diagnosed

Doctors use a "triple assessment":

1. Clinical breast exam.
2. Imaging: ultrasound is the main test under 30 to 40, because young breast tissue is dense on mammograms. A mammogram is added for older women.
3. Core needle biopsy: a few thin cores of tissue are taken with local anesthetic under ultrasound guidance. This confirms the lump is a fibroadenoma rather than a phyllodes tumor or cancer.

In young women, a small lump with classic benign features on ultrasound is sometimes followed with repeat scans rather than biopsied, depending on local guidelines.

Treatment

Watchful waiting

Most simple fibroadenomas need no treatment. Many stay the same size, and about a third shrink or disappear over several years. Follow-up typically involves a repeat ultrasound at around 6 months, then routine breast awareness.

Removal

Removal is considered when:

• The lump is larger than about 2 to 3 cm or is growing
• The biopsy is unclear or suggests a phyllodes tumor
• It causes pain or changes the shape of the breast
• You prefer to have it out for peace of mind

Options include:

• Surgical excision (lumpectomy): removal through a small cut, often around the areola edge, usually as day surgery.
• Vacuum-assisted excision: a needle-based technique under ultrasound that removes smaller fibroadenomas through a tiny cut.
• Cryoablation: freezes the lump in place. The body reabsorbs it over months.

New fibroadenomas can develop later in the same or the other breast. This is not a recurrence of the old one.

Can a fibroadenoma turn into cancer?

Very rarely. A simple fibroadenoma does not meaningfully raise breast cancer risk. Complex fibroadenomas are linked to a slightly higher long-term risk, comparable to other benign breast changes. Cancer arising inside a fibroadenoma is extremely rare. Continue normal breast screening for your age and report any change.

Living with a fibroadenoma

Get to know how your breasts normally look and feel, and report new lumps or changes. Fibroadenomas do not affect breastfeeding in most cases. Pregnancy can make them grow temporarily. Hormonal contraception has not been shown to cause them.

Frequently asked questions

What does a fibroadenoma feel like?

It usually feels like a smooth, firm, rubbery marble that slips away under your fingers when you press it. It is typically painless and well defined. Some people notice slight tenderness before a period. A lump that is hard, irregular or stuck to the skin or chest wall needs prompt checking.

Can a fibroadenoma go away on its own?

Yes. Many fibroadenomas stay the same size for years, and roughly a third shrink or disappear, especially as you approach menopause and estrogen levels fall. Some grow, particularly in teenagers or during pregnancy. Regular checks track any change.

Does a fibroadenoma need to be removed?

Not usually. Simple fibroadenomas confirmed by imaging and biopsy can be left alone. Removal is advised for large or growing lumps, unclear biopsy results, or if a phyllodes tumor is suspected. Some people choose removal because the lump bothers them or causes anxiety.

Can fibroadenoma cause pain?

Most fibroadenomas are painless. Some become tender in the days before a period or during pregnancy because they respond to hormones. Ongoing breast pain is more often due to normal hormonal changes or fibrocystic breasts than to a fibroadenoma itself.

Can men get fibroadenomas?

They are very rare in men because men lack the breast lobules that fibroadenomas grow from. A breast lump in a man is more often gynecomastia, a harmless growth of breast tissue, but any lump in a man should be checked by a doctor.