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1. What is a borderline or malignant phyllodes tumour?
2. Symptoms of phyllodes tumour
3. Who is affected?
4. Diagnosis 
5. Treatment of borderline or malignant phyllodes tumours
6. Follow-up after treatment
7. Further support

1. What is a borderline or malignant phyllodes tumour?

A phyllodes tumour is a growth of cells that forms a hard lump in the breast.

Phyllodes tumours can be:

  • benign (not cancer)
  • malignant (cancer)
  • borderline (somewhere between benign and malignant)

This information is about borderline and malignant phyllodes tumours. You can also read our information about benign phyllodes tumours.

Phyllodes tumours are usually treated with surgery. 

Most people with borderline phyllodes tumours have no further problems after treatment. 

For people with a malignant phyllodes tumour, the outlook (prognosis) after treatment is usually good.

2. Symptoms of phyllodes tumour

A phyllodes tumour can usually be felt as a smooth, hard lump in the breast.

Sometimes it can be seen as a smooth bulge under the skin.

Occasionally phyllodes tumours are fast-growing and become quite large.

Phyllodes tumours are sometimes found during breast screening before they cause any noticeable symptoms.

3. Who is affected?

Borderline and malignant phyllodes tumours are rare. 

They are most common in women between 40 and 50 who haven’t yet been through the menopause, although they can occur at any age. 

Phyllodes tumours can also occur in men, although this is very rare.

4. Diagnosis

Phyllodes tumours are diagnosed using a number of tests, which may include:

  • a mammogram (breast x-ray) 
  • an ultrasound scan (uses sound waves to produce an image) 
  • a core biopsy (using a hollow needle to take a sample of breast tissue to be looked at under a microscope – several tissue samples may be taken at the same time) 

Your specialist may also suggest you have an MRI (magnetic resonance imaging) scan. This uses magnetism and radio waves to produce a series of images of the inside of the breast. An MRI doesn’t expose the body to x-ray radiation.

For more information about these tests, read about what to expect at a breast clinic appointment.

Phyllodes tumours are often difficult to diagnose because they can be confused with other breast problems, particularly a benign breast condition called a fibroadenoma. This means your specialist team may not be sure of the diagnosis until the whole tumour is removed and examined. Sometimes the tumour will need to be sent to another hospital for further assessment. 

5. Treatment of borderline or malignant phyllodes tumours 


Surgery is usually the main treatment for borderline or malignant phyllodes tumours. 

There are two main types of breast surgery:

  • breast-conserving surgery, also known as a wide local excision or lumpectomy – removal of the tumour with a wide margin (border) of normal breast tissue around it 
  • mastectomy – removal of all the breast tissue including the nipple area 

The type of surgery recommended depends on the position of the tumour and the size of the tumour relative to the size of your breast. Your breast surgeon will discuss this with you.

Borderline or malignant phyllodes tumours rarely spread to the lymph nodes (glands) under the arm, so these will not usually be removed during surgery. However, your surgeon will look at your individual case and recommend the best surgery for you.

Adjuvant (additional) treatments

After surgery, some people may need further treatments. These are called adjuvant treatments.

If this is the case, your specialist team will be able to tell you if there are any clinical trials you could take part in. 


Radiotherapy uses high energy x-rays to destroy cancer cells. 

Malignant phyllodes tumours are more likely to be treated with radiotherapy after surgery to reduce the risk of the tumour returning in the same breast. 


Chemotherapy destroys cancer cells using anti-cancer drugs. 

While people with phyllodes tumours don’t usually have chemotherapy, it may be offered if a malignant phyllodes tumour has spread outside the breast. 

5. Follow-up after treatment

Borderline or malignant phyllodes tumours do not usually come back after treatment, although sometimes the tumours can return. The risk is higher with malignant tumours. 

You will be offered follow-up appointments for a number of years depending on your individual situation. 

After your treatment, you may have regular mammograms. If you have had breast-conserving surgery, you will have a mammogram on both breasts. If you have had a mastectomy, with or without reconstruction, you will only have a mammogram on your other breast.

You may also be offered an ultrasound scan.

It’s important to be breast aware and call your breast care nurse or go back to your GP if you notice any changes in your breasts, regardless of how soon these occur after your diagnosis of a phyllodes tumour.

6. Further support

Being told you have a borderline or malignant phyllodes tumour can make you feel anxious, lonely and isolated. Having a rarer type of breast tumour may add to your anxiety. However, there are people who can support you, so don’t be afraid to ask for help if you need it. Let other people know how you are feeling, particularly family and friends so they can support you.

Some people find it helpful to discuss their feelings and concerns with their breast care nurse or specialist. If you want to talk through your feelings and concerns in more depth over time, a counsellor or psychologist may be more appropriate. Your breast care nurse, specialist or GP can arrange this.

If you would like any further information and support about phyllodes tumours or just want to talk things through, you can speak to one of our nurses by calling our free Helpline on 0808 800 6000.

Last reviewed: October 2019
Next planned review begins 2021

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