Most breast lumps are not breast cancer and will never develop into breast cancer. The safest approach to all breast lumps however is to always get a lump examined by a medical professional. In fact no matter how often you examine breasts as a doctor or check your own breasts as a patient, it can’t be assumed that the breast lump is of no concern. A clinical examination together with a simple non-threatening non painful investigation called an ultrasound or breast sonar (done by a radiologist, with a mammogram if over 35 years) is the easiest way to tell what the breast lump could be.

The safest approach to all breast lumps however is to always get a lump examined by a medical professional.

Many years ago we used to categorise breast masses according to the age groups where they occurred, but this can be confusing.  A far safer approach is to look at how breast masses are seen with ultrasound (breast sonar).  We want to emphasise that it is most important to determine that the lump is not a cancer.  The triple assessment of a clinical examination, either sonar and/or a mammogram should be obtained as well as a core needle biopsy if required.

Solid masses


These are highly mobile round, smooth, firm lumps usually found in a young woman’s breast (the teenager and the girl in her early twenties). It is sometimes called the breast mouse because it is so mobile and ‘runs’ from the examining hand.  Sometimes they do occur in older women but not often. Fibroadenomas come from the lobules (milk tissue) and react to female hormones like the other breast tissue they develop from.

Most fibroadenomas get noticed around 1-2cm in size but they can grow to even more than 5 cm. Women who have one, often find more when they start looking and it’s not uncommon to find lots, and in both breasts. A fibroadenoma is quite innocent, and almost never related to cancer. Having a fibroadenoma doesn’t even increase your risk of cancer. If the doctor is sure your lump is a fibroadenoma (after confirming it on ultrasound and a core needle biopsy result because clinical exam alone can be wrong in half of all cases) it can be left well alone if it is not bothersome. It may disappear spontaneously.

If the fibroadenoma becomes painful, if it gets bigger than 3cm (that makes it a giant fibroadenoma) or if you are worried about it, it can be removed with surgery from a cut around the nipple. However remember that surgery leaves both scars on the skin and in the breast tissue and can make breast investigations later in life more difficult to read.

If you already have a fibroadenoma and are pregnant, during pregnancy and lactation you can expect the size may vary but they will not interfere with breast feeding or milk coming in.  Calcified fibroadenomas are sometimes found in the elderly women as a hard discrete mobile lump that can be easily seen on a mammogram.

Know your normal.

Check your breasts.

Cystosarcoma Phyllodes (Phyllodes Tumour)

Phyllodes tumours (PTs) take their name from the Greek word phyllon which means ‘leaf’ because of their leaf-shaped growth pattern. They can also behave like plants which are difficult to root out, like a weed in the garden. Unlike fibroadenomas, when they grow in the breast, they don’t form a neat shell around the outside, but instead they grow into normal breast tissue. That means when they are removed with surgery, if a rim of normal breast tissue is not taken out too, little bits can be left behind. Like the roots of a weed, they will cause the lump to grow back, often more aggressively than before.

Phyllodes do have a risk of a recurrence even if they are benign (non-cancerous), but they also have a risk of spreading or recurring if malignant (cancerous). The type of tumour and its risk to recur or spread (metastasise) can only be determined once it has been removed and examined microscopically. Once the grade of a Phyllodes tumour is established, you’ll need to undergo a second surgical procedure to ensure you have clear margins of disease- free tissue of 1-2 cm, followed by reconstruction. The reconstructive options depend on many factors. If you’re large-breasted and the tumour is relatively small, reconstruction can be done in a similar way to a breast reduction. If the tumour is large and most of your breast needs to be removed, the reconstruction will be more extensive and involved.

Unlike ‘normal’ breast cancer there are no identified risk factors for having a Phyllodes tumour, nor does there seem to be a genetic predisposition. And unlike ‘normal’ breast cancer which arises from the glandular elements of the breast, these are tumours of the connective tissue within the breast tissue. Malignant Phyllodes tumours don’t spread like breast cancers to lymph glands and usually just recur locally, however the more aggressive tumours can spread to the lungs and liver. Some can be so large (up to 30 cm in size) that complete removal of the breast and part of the chest wall is required

Because doctors don’t encounter Phyllodes tumours all that frequently, they are often misdiagnosed as benign fibroadenomas, the most common kind of breast masses that occur especially amongst younger women. Breast masses should never be brushed off as ‘harmless fibroadenomas’ and that is why most diagnoses today should only be undertaken by a specialist radiologist with the use of an ultrasound.

Any features on ultrasound that are not typical should result in a core needle biopsy, which involves a small biopsy done under local anaesthetic.  ALL masses, irrespective of diagnosis, should be followed up 6 months later by an ultrasound. Furthermore any masses that grow, or are larger than 3cm, should always be excised

Fat necrosis

Severe injury to the breast (from a motor vehicle accident or being punched in the breast) can cause fat necrosis. It is also seen after some breast reduction operations. The problem is that fat necrosis feels like a hard irregular lump, which can feel a lot like a mimic breast cancer.  The only way to tell the difference is through a mammogram and core needle biopsy which will usually help tell the difference. There is no treatment required for this problem, surgery is not advisable, and once the investigations have confirmed that the lump is fat necrosis, reassurance and watching it doesn’t get bigger or change is all that is needed.

Breast hamartomas (Fibroadenolipoma)

This is not a common breast lump, and not the first thought of most doctors. Hamartomas of the breast are normally painless breast lumps which are softer and larger. They have been called a ‘breast within the breast’ because they contain all the different types of tissue found in a breast. This may account for some diagnostic confusion especially if an FNA is performed, as the cells are difficult to differentiate from abnormal cells. It is normally possible to confirm diagnosis with a core biopsy rather than an FNA. Even on a mammogram these lumps have a distinct picture showing an easy to see lump separated from normal breast tissue by a thin white margin. If clinical examination and core needle biopsy do not fully explain the lump, a surgical removal is recommended.

Fibroadenosis (and cyclical breast pain)

Breasts alter cyclically with the different stages of the menstrual cycle.  In the week prior to menstruation, the breast normally increases in size and sometimes becomes nodular, with pain. This can mimic a breast mass.

This is normally called ‘fibroadenosis’ but we think this term can be confusing and misleading sometimes because represents what is going on inside the breast at a tissue level but the process is normal. Breasts are uniquely different to palpation, some are smooth, some are nodular and the term should not be used as if this is abnormal or a disease of the breast.

All breasts have a certain amount of fibrosis (connective tissue) and adenosis (gland or milk tissue) and disease should be attributed to a woman with breast symptoms. If concerned, a breast ultrasound can aid the clinician in determining whether this is a mass or just nodularity.

Cystic masses

Breast Cysts

Breast cysts are masses that might look and feel like a lump but actually they are fluid-filled sacs within the breast. No one knows why they form but it can be due to the hormonal or structural changes in the breast that happen as you get older. Cysts usually occur in the premenopausal women in the years after childbirth and breast feeding (thirty-five to fifty years) and they develop in about 5% of women. They might be single or multiple, but often they are only picked up on mammogram or sonar. The most important information about pure breast cysts is that they do not cause cancer and they are no associated with cancer. They are easily diagnosed using sonar (ultrasound) and can be aspirated with a fine needle (FNA).  The fluid is usually yellow or greenish and there can be up to 20mls.

Provided there is no blood (red or black) in this fluid and that there is no residual lump remaining after the aspiration, no further treatment is necessary.  If there is blood or a residual lump, further evaluation is mandatory.  This takes the form of sending the aspirate for cytology (it is a good principle to send all aspirates for cytology) and then to biopsy the residual mass if present under radiological guidance or to excise it surgically.


This is simply a cyst, found only in breast feeding women that contains retained milk but has no signs of bacterial infection.  It can be treated by needle aspiration of the cyst and suppression of milk. Uncommonly surgical excision can also be performed if necessary.