Most breast lumps are caused by benign (non-cancerous) conditions, although occasionally a breast lump can be a symptom of breast cancer.

It’s important to see your GP as soon as possible if you notice a lump in your breast so they can refer you for tests to confirm the cause. Read more about diagnosing breast lumps.

Some of the main causes of breast lumps and their symptoms are outlined below.

Benign breast lumps

There are a number of different benign causes of breast lumps. Most benign breast lumps are harmless and may not necessarily require any treatment.

It’s also important to remember that benign breast lumps will not become cancerous and do not increase your risk of developing breast cancer in the future.

Fibroadenosis

Fibrocystic breast disease, also known as fibroadenosis, is a term used to describe a group of benign conditions that affect the breast. The symptoms of fibroadenosis can include:

• breast pain (mastalgia or mastodynia)
• increase in breast size
• lumpiness of the breast (nodularity), particularly just before or during a period

Fibroadenosis can develop in one or both breasts, or can affect just part of one breast. The symptoms can also vary significantly between women, with some women finding them slightly annoying and others finding them very painful. The pain and lumpiness will usually disappear after your period.

The cause of fibroadenosis is not well understood. However, it may be the result of the breast tissue responding abnormally to hormonal changes that occur with the menstrual cycle.

Fibroadenomas

Fibroadenomas are smooth, well-rounded solid lumps of tissue that sometimes develop outside the milk ducts (the tiny tubes in the breast that carry milk). They are particularly common in young women.

They are sometimes described as “breast mice” because they can easily move around within the breast.

Fibroadenomas can disappear on their own, but they sometimes remain and grow larger, particularly during pregnancy. They don’t usually resolve after your period.

It’s not clear what causes fibroadenomas, but it is thought they may occur because of an abnormal response to the hormone oestrogen. This is because they are common in women who haven’t been through the menopause and postmenopausal women who are having hormone replacement therapy (HRT).

Breast cysts

Breast cysts are fluid-filled sacs that develop within the breast tissue and can cause smooth, firm lumps to develop. They are more common in women aged 30 to 60.

Cysts vary in size. Some can be tiny, while others can grow to several centimetres in diameter. Single or multiple cysts can occur in one or both breasts.

Cysts often do not cause any symptoms, although some women may experience pain in addition to any lumps.

As with fibroadenomas, hormones are thought to play a role in the development of breast cysts because they are particularly common in pre-menopausal women and postmenopausal women having HRT.

Breast abscesses

A breast abscess is a painful collection of pus that forms inside the breast.

In addition to a painful lump, symptoms of a breast abscess can include a high temperature (fever) and inflammation (redness and swelling) of the skin over the affected area.

Most breast abscesses are caused by a bacterial infection. The bacteria usually enter the breast through small cracks or breaks in the skin of the nipple, which can sometimes develop during breastfeeding.

Other benign causes

Other benign causes of breast lumps include:

• mastitis – where breast tissue becomes painful and inflamed
• fat necrosis – a hard, irregular lump often caused by trauma or bruising to the breast; for example, after surgery on the breast
• a lipoma – a fatty growth that causes a lump
• an intraductal papilloma – a wart-like growth in a milk duct, which may also cause nipple discharge

Breast cancer

Although the vast majority of breast lumps are benign, a lump in one of the breasts can sometimes be a sign of breast cancer in women and breast cancer in men.

A lump is more likely to be a sign of breast cancer if it:

• is clearly defined
• feels firm
• doesn’t move around
• persists after a period or develops after the menopause (in women)

Breast cancer can also cause some other symptoms, such as discharge from your nipples, dimpling on the skin of your breasts, and changes in the appearance of your nipple (such as becoming sunken into your breast).

The risk of breast cancer increases with age, but is most common in women and men over the age of 50. Having a family history of the condition may also mean your risk is increased.

Read more about the symptoms of breast cancer in women and symptoms of breast cancer in men.

It is important to be aware of how your breasts usually look and feel so you can quickly pick up on any changes that may occur.

See your GP if you notice a lump in your breast or any change in its appearance, feel or shape. Your GP may ask a number of questions, including:

• When did you first noticed the lump?
• Do you have other symptoms, such as pain or a discharge from your nipple?
• Do your symptoms change with your menstrual cycle?
• Have you ever injured your breast?
• Do you have any risk factors for breast cancer, such as a close family member who has had breast cancer?
• What medications are you currently taking?
• Are you currently breastfeeding, or have done in the past?

Your GP will also carry out a physical examination of both your breasts, with your permission. 

If it makes you feel more comfortable about being examined, you can bring a friend or a family member with you. But your GP should ask you whether you’d like another staff member – such as a practice nurse – to be present while your breast is being examined.

After asking about your symptoms and examining your breasts, your GP may refer you for further tests to confirm the cause of the lump.

Being referred for further testing can be scary, but it is important to remember that this is routinely done and it does not necessarily mean your GP thinks you have breast cancer. Most people who have these further tests are eventually found to have a benign (non-cancerous) condition.

The main tests you may have are described below.

Mammogram

A mammogram is a simple procedure that uses X-rays to create an image of the inside of your breasts.

It can help identify early changes in your breast tissue. Younger women usually have denser breasts than older women, which makes changes more difficult to identify.

This means that mammograms are not as effective in women under the age of 40. If you are under 40, your GP may suggest you have a breast ultrasound instead.

If you need to have a mammogram, a radiographer (an X-ray specialist) will position one of your breasts on a flat X-ray plate.

A second X-ray plate will press down on your breast from above so it is temporarily flattened between the two plates. An X-ray will then be taken, which will produce a clear image of the inside of your breast.

After the first X-ray has been taken, the same procedure will be carried out on your other breast.

A mammogram only takes a few minutes to carry out, but you may find it a bit uncomfortable or even slightly painful. After the procedure is complete, the image of your breast will be examined for anything unusual.

Ultrasound scan

If you are under the age of 40, a breast ultrasound scan may be recommended because your breast tissue may be too dense for a mammogram.

However, women over 40 will often have both a mammogram and breast ultrasound scan to investigate a breast lump.

Your doctor may also suggest you have a breast ultrasound scan if they need to know whether a lump in your breast is solid or contains liquid.

Ultrasound scans use high-frequency sound waves to produce an image of the inside of your breasts. An ultrasound probe or sensor will be placed over your breasts to create an image on a monitor. The image will highlight any lumps or abnormalities that may be present.

Biopsy

You may need a breast biopsy if the cause of your breast lump cannot be diagnosed using a mammogram or ultrasound scan. A biopsy is a procedure that involves removing a tissue sample from the lump for further testing. 

To obtain the sample, a hollow needle is inserted through your skin and into the area being examined. Ultrasound scans or X-rays will be used to help the doctor or surgeon guide the needle to exactly the right place.

When the needle is in position, it will “suck out” a sample of tissue. A local anaesthetic will usually be used to numb the area so you won’t feel pain or discomfort.

Breast lumps are common and have a number of different causes.

Although most lumps aren’t breast cancer, any unusual changes to the breasts should be checked by a GP as soon as possible. If your GP finds a lump on examination, they will routinely refer you to be seen by a hospital specialist.

There are several types of benign (non-cancerous) breast lump, most of which are harmless and are caused by hormonal changes that occur at different times in a woman’s life, such as during the menstrual cycle.

Common types of benign breast lump include:

• a fibroadenoma – a firm lump that moves around easily in the breast and is more common in younger women
• a breast cyst – a smooth, firm fluid-filled lump most commonly seen in women aged 30 to 60
• a breast abscess – a painful collection of pus that forms under the skin of the breast, usually as the result of a bacterial infection

Benign breast lumps will not turn into breast cancer and do not increase your risk of developing breast cancer in the future.

Read more about the causes of breast lumps.

Checking your breasts

It’s important to be “breast aware” so you can identify any problems in your breasts and get them checked out as soon as possible. This means being familiar with your breasts and what is normal for them, and examining them regularly for any changes.

If you are 50 years or over, it’s also important to attend breast cancer screening appointments every three years, where a type of X-ray called a mammogram will be carried out to look for early signs of cancer.

But don’t wait until your next screening appointment if you notice any problems in your breast. See your GP right away.

Seeing your GP

It is important you see your GP as soon as possible if you notice a lump in your breasts so a cause can be confirmed. Finding a lump in your breast can be a worry, but around 90% of breast lumps are benign.

You also should see your GP if you notice any other changes to one or both of your breasts, such as:

• an area of thickened tissue
• nipple discharge, which may contain blood
• a change in the size or shape of your breasts
• dimpling on the skin of your breasts
• a rash on or around your nipples
• a change in your nipple’s appearance – for example, becoming sunken into your breast
• persistent pain in your breasts or armpits
• a lump or swelling in your armpits

Your GP will ask you about your symptoms and will then ask your permission to examine your breasts. You should also be asked whether you’d like another staff member – such as a practice nurse – to be present while your breast is being examined.

Further tests

Your GP may then refer you for further tests, such as an ultrasound scan and mammogram, to determine the cause.

Being referred for further testing can be scary, but it does not necessarily mean your GP thinks you have breast cancer. Most people who have these further tests are eventually found to have a benign condition.

Read more about diagnosing breast lumps.

How breast lumps are treated

Benign breast lumps do not necessarily require any treatment, although treatment may be recommended if the lump is particularly large, is getting bigger, or is causing other symptoms such as pain.

Medication can often help relieve breast pain, and antibiotics can treat any bacterial infections that may have caused the lump to develop.

In some cases, a needle may need to be used to drain away any fluid or pus within the breast lump. Local anaesthetic will be used to numb the area being treated so you don’t feel any pain while this is carried out.

Occasionally, surgery may be carried out to cut out the lump. This will normally be done under general anaesthetic (where you are asleep) and you will usually be able to go home the same day.

Read more about treating breast lumps.

The Map of Medicine is used by doctors throughout the NHS to determine the best treatment options for their patients. NHS Choices offers everyone in England exclusive and free access to this cutting-edge internet resource, which lets you see exactly what your doctor sees.

The information in the Map has been approved by the UK’s leading clinical experts, is based on the best available clinical evidence, and is continually updated. To take advantage of this unique resource go to:

Map of Medicine: breast disease

How a breast lump is treated will largely depend on the underlying cause and any other symptoms you have.

Benign breast lumps often do not need to be treated unless they are particularly large or painful, or are getting bigger.

Some types of benign breast lump, such as fibroadenomas, breast cysts and fat necrosis, may improve over time without any treatment.

If treatment is not necessary, you may be asked to return to your GP if you notice any further changes to your breasts.

The main treatments for benign breast lumps are described below.

Medication

Medication may be recommended if your breast lump is causing pain or is the result of an infection.

Some of the medications that may be used include:

• painkillers, such as paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs)
• tamoxifen, danazol or bromocriptine are very occasionally used to treat breast pain
• antibiotics to treat breast abscesses caused by bacterial infections

For some, simple measures such as reducing the amount of saturated fat in your diet and wearing a well-fitting bra to support your breasts may also help reduce pain.

Drainage

In some cases, any fluid or pus contained within a breast cyst or a breast abscess may need to be drained. This is known as aspiration.

During the aspiration procedure, local anaesthetic is used to numb the area being treated and a needle is guided into place using ultrasound scans so the fluid or pus can be removed. In rare cases, a small cut may be made into an abscess to drain the pus.

The fluid sample may then be sent for testing to confirm the diagnosis.

Sometimes breast cysts that have been drained can refill. You should always visit your GP if you notice any changes to your breasts after treatment. A cyst can be drained again, but you may need surgery to remove it if it keeps refilling.

Surgery

If a benign lump is particularly large or is getting bigger, surgery may be carried out to remove it.

Types of benign breast lumps that may sometimes need to be removed with surgery include fibroadenomas, breast cysts, fat necrosis and intraductal papillomas.

The surgical procedure to cut out a lump in your breast is called a lumpectomy and is usually carried out under general anaesthetic. In some cases, a special vacuum is used during the procedure to suck out the tissue forming the lump.

Once it is removed, the lump will be sent for testing to confirm the diagnosis.

You will usually be able to go home the same day of the operation. Possible risks and side effects of the operation can include temporary bruising, swelling or bleeding, and an infection in the treated area.