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Hyperplasia and atypical hyperplasia

Hyperplasia is a benign (not cancer) breast condition. Learn about what it is, how it is diagnosed and how it can be treated.

1. What is hyperplasia?

Hyperplasia is a benign (not cancer) breast condition.

It does not usually cause any symptoms in the breast.

Hyperplasia happens when there’s an increase in the number of cells lining the ducts (tubes that carry milk to the nipple) or lobules (milk-producing glands) of the breast. 

Side-on illustration of the breast, with arrows to the chest, lobules, nipple, ducts, fatty tissue and ribs
Side-on diagram of the breast.
Side-on diagram of the breast.

When hyperplasia occurs in the ducts it’s called ductal hyperplasia. Ductal hyperplasia can be either "usual" or "atypical". Atypical means "not typical".

When hyperplasia occurs in the lobules it’s called atypical lobular hyperplasia.

2. Atypical hyperplasia

Atypical hyperplasia happens when cells lining the ducts or lobules increase in number and develop an unusual pattern or shape.

Atypical hyperplasia is also benign (not cancer). However, having atypical hyperplasia has been shown to slightly increase the risk of breast cancer in some people. 

3. Who it affects

Hyperplasia usually develops naturally as the breast changes with age. It’s more common in women over 35 but can affect women of any age.

Hyperplasia and atypical hyperplasia can also affect men, but this is very rare.

4. Diagnosis

Hyperplasia and atypical hyperplasia do not usually cause any symptoms. Because of this, they’re usually found by chance when breast tissue that has been removed during a  or breast surgery is examined under a microscope in the laboratory.

5. Treatment and follow-up

Usual ductal hyperplasia 

Usual ductal hyperplasia does not usually need any treatment or follow-up.

Atypical ductal or lobular hyperplasia 

Surgical excision biopsy

Your doctor may want you to have an operation called an excision biopsy to remove the atypical hyperplasia. This can be done under local or general anaesthetic.

The breast tissue removed will be examined under a microscope, which can help confirm the diagnosis.

Your surgeon may use dissolvable stitches placed under the skin. These will not need to be removed. However, non-dissolvable stitches will need to be taken out a few days after surgery. Your treatment team will give you information about this and about looking after the wound.

The operation will leave a scar, but this will fade over time.

Vacuum assisted excision biopsy

You may be offered a vacuum assisted excision biopsy to remove the atypical hyperplasia. 

After an injection of local anaesthetic, a small cut is made in the skin. 

A special needle connected to a vacuum device is placed through this cut. Using mammogram or ultrasound as a guide, breast tissue is sucked through the needle by the vacuum into a collecting chamber. 

The biopsy device is used until the area being investigated has been removed. This may mean you can avoid having an operation under general anaesthetic. 

The tissue removed is sent to a laboratory to be examined under a microscope.


You may have follow-up if you have had a surgical excision biopsy or a vacuum assisted excision biopsy. However, follow-up is decided on a case by case basis. Your treatment team will let you know whether you need follow-up.

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Quality assurance

This information was published in August 2023. Information under review as of March 2024.

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