Hyperplasia and atypical hyperplasia

Hyperplasia is a breast condition that is benign (not cancer). 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 doesn’t usually cause any symptoms, such as a lump or pain, and is usually found by chance.

Hyperplasia happens when there’s an increase in the number of lining the ducts or lobules 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’.

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

2. Atypical hyperplasia

Atypical hyperplasia is when cells lining the ducts or lobules increase in number and also develop an unusual pattern or shape. ‘Atypical’ means ‘not typical’.

Atypical ductal hyperplasia (ADH) occurs in the ducts; atypical lobular hyperplasia (ALH) occurs in the lobules. 

Atypical hyperplasia is 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

As hyperplasia and atypical hyperplasia don’t usually cause any symptoms, they’re usually found by chance when breast tissue that has been removed during a biopsy 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 

Once a diagnosis of atypical hyperplasia is confirmed following a biopsy, your specialist may recommend a small operation to remove the atypical hyperplasia. 

Alternatively, 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 hollow probe connected to a vacuum device is placed through this. Using a or ultrasound as a guide, breast tissue is sucked through the probe by the vacuum into a collecting chamber. The biopsy device is used until the area being investigated has all been removed. This may mean that an operation under a general anaesthetic can be avoided. The tissue removed is sent to a laboratory to be examined under a microscope. 

Your specialist is likely to want you to have follow-up, which is usually a mammogram every one to two years. How often and for how long you go for follow-up will depend on what happens in your local area. 

6. What this means for you

Having usual ductal hyperplasia doesn’t increase your risk of developing breast cancer. However, it’s still important to be breast aware and go back to your GP if you notice any changes in your breasts regardless of how soon these occur after your diagnosis of hyperplasia. 

If you have atypical hyperplasia, you may be worried or anxious that your risk of breast cancer is slightly increased. However, most people with atypical hyperplasia will not develop breast cancer. It’s important to go to your follow-up appointments, continue to be breast aware and go back to your GP if you notice any changes regardless of how soon they appear after your diagnosis of atypical hyperplasia. 

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Last reviewed in November 2018. The next planned review begins in January 2023.

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