Atypical hyperplasia of the breast

Overview

Atypical hyperplasia of the breast is the development of precancerous cells in the breast. Atypical hyperplasia causes a buildup of cells in the breast tissue. When viewed with a microscope, the cells look different from typical breast cells.

Atypical hyperplasia of the breast isn't breast cancer. But it's a sign that you have an increased risk of breast cancer in the future.

Your healthcare team creates a plan to help you manage your risk of breast cancer. Often this includes more-frequent breast cancer screening tests. You also might consider medicines to reduce breast cancer risk.

Main parts of the breast

Symptoms

Atypical hyperplasia of the breast usually doesn't cause any symptoms.

Atypical hyperplasia of the breast is typically found during a breast biopsy. A breast biopsy is a procedure to remove some breast cells for testing. It's often recommended if something concerning is found on a mammogram or an ultrasound. A biopsy also might be done to investigate a breast concern, such as a lump.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

Causes

It's not clear what causes atypical hyperplasia of the breast.

Atypical hyperplasia of the breast happens when cells in the breast tissue develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. The changes tell the cell to make many more cells. This causes a buildup of cells in the breast. Healthcare professionals call this buildup hyperplasia. The changes also turn the cells into atypical cells. This means that the cells look different from typical cells.

Atypical hyperplasia is thought to be a very early step in the process that turns healthy cells into cancer cells. In theory, if atypical hyperplasia cells are allowed to continue growing, they could get more DNA changes and become cancer cells. More research is needed to understand how this happens.

Atypical hyperplasia can happen in the breast ducts or the breast lobules:

  • Atypical ductal hyperplasia describes a growth of atypical cells within the breast ducts. The breast ducts are tubes that can carry breast milk to the nipple. This type of atypical hyperplasia is most common.
  • Atypical lobular hyperplasia describes a growth of atypical cells within the breast lobules. The breast lobules are glands that can make breast milk. This type of atypical hyperplasia is less common.

Both types of atypical hyperplasia increase the risk of breast cancer. Treatment for both types is similar.

How breast cancer develops

Risk factors

There are no specific risk factors for atypical hyperplasia of the breast. Atypical hyperplasia is one of several conditions that cause a growth of cells in the breast that isn't cancerous. These conditions are sometimes called benign breast diseases. Healthcare professionals have found risk factors for benign breast diseases. They include:

  • A family history of breast cancer. If a parent, sibling or child had breast cancer, your risk of being diagnosed with atypical hyperplasia of the breast or another benign breast disease before menopause is increased.
  • Menopausal hormone therapy. Taking certain hormone therapy medicines to control the symptoms of menopause may increase the risk of atypical hyperplasia and other benign breast diseases.

Complications

If you've been diagnosed with atypical hyperplasia of the breast, you have an increased risk of getting breast cancer in the future. The risk of breast cancer in those with atypical hyperplasia is about four times higher than in those who don't have atypical hyperplasia. The risk is similar for atypical ductal hyperplasia and atypical lobular hyperplasia.

Studies of women with atypical hyperplasia have found that the risk of breast cancer increases over time. At 25 years after diagnosis, about 30% of women with atypical hyperplasia may have breast cancer. Put another way, for every 100 women diagnosed with atypical hyperplasia, 30 can be expected to have breast cancer 25 years after diagnosis. And 70 will not develop breast cancer.

Prevention

It's not clear whether there's anything that can prevent atypical hyperplasia of the breast. The same things that help lower the risk of breast cancer may help lower the risk of atypical hyperplasia. Things you can do to lower your risk of breast cancer include:

Ask about breast cancer screening

Talk with your doctor or other healthcare professional about when to begin breast cancer screening. Ask about the benefits and risks of screening. Together, you can decide what breast cancer screening tests are right for you.

Become familiar with your breasts through breast self-exam for breast awareness

You may choose to become familiar with your breasts by occasionally inspecting them during a breast self-exam for breast awareness. If there is a new change, a lump or something not typical in your breasts, report it to a healthcare professional right away.

Breast awareness can't prevent breast cancer. But it may help you to better understand the look and feel of your breasts. This might make it more likely that you'll notice if something changes.

Drink alcohol in moderation, if at all

Limit the amount of alcohol you drink to no more than one drink a day, if you choose to drink. For breast cancer prevention, there is no safe amount of alcohol. So if you're very concerned about your breast cancer risk, you may choose to not drink alcohol.

Exercise most days of the week

Aim for at least 30 minutes of exercise on most days of the week. If you haven't been active lately, ask a healthcare professional whether it's OK and start slowly.

Limit menopausal hormone therapy

Hormone therapy treatments used to ease menopause symptoms may increase the risk of breast cancer. Talk with a healthcare professional about the benefits and risks of hormone therapy.

Some people have symptoms during menopause that cause discomfort. These people may decide that the risks of hormone therapy are acceptable to get relief. To reduce the risk of breast cancer, use the lowest dose of hormone therapy possible for the shortest amount of time.

Maintain a healthy weight

If your weight is healthy, work to maintain that weight. If you need to lose weight, ask a healthcare professional about healthy ways to lower your weight. Eat fewer calories and slowly increase the amount of exercise.

Diagnosis

Atypical hyperplasia of the breast is most often diagnosed during a breast biopsy. A breast biopsy is a procedure to remove a sample of breast tissue for testing. It's often done if something concerning is found during a clinical breast exam or on an imaging test, such as a mammogram or an ultrasound.

Treatment

Treatment for atypical hyperplasia of the breast may involve surgery to remove the atypical cells. Not everyone needs surgery. Your healthcare team might recommend more-frequent breast cancer screening to watch for signs of breast cancer. You also might consider medicine to lower your risk of breast cancer.

Surgery

Atypical hyperplasia of the breast may be treated with surgery to remove the atypical cells. This might be recommended if mammogram images show something concerning. Members of your healthcare team typically decide whether to recommend surgery based on a discussion of your imaging test results, the results of your breast biopsy and other factors.

If you have surgery, the tissue removed during the operation is tested in the lab to look for signs of cancer. Most people who have surgery for atypical hyperplasia don't have breast cancer. But sometimes the surgery finds noninvasive breast cancer, also called ductal carcinoma in situ, or invasive breast cancer.

Not everyone with atypical hyperplasia of the breast needs surgery. Some healthcare teams may not recommend surgery if there is a low risk of finding cancer. The level of risk may depend on the findings of your mammogram images and other factors, such as your medical history and past breast operations. Your healthcare team carefully considers your biopsy results and your other health conditions when choosing the treatment plan that's best for you.

Medicine to lower the risk of breast cancer

Medicines that block the hormone estrogen in the body can lower the risk of breast cancer. Most breast cancers use estrogen and other hormones to help the cancer grow. Blocking estrogen helps stop cancer from forming.

Hormone-blocking medicines that are used to lower breast cancer risk include:

  • Tamoxifen
  • Raloxifene (Evista)
  • Anastrozole (Arimidex)
  • Exemestane (Aromasin)

These medicines are typically taken daily for five years to reduce the risk of breast cancer. The medicine tamoxifen is sometimes taken in a lower dose every other day. Talk with your healthcare team about which medicine is best for you.

Careful monitoring for breast cancer

Atypical hyperplasia of the breast increases the risk of breast cancer. So your healthcare team creates a breast cancer screening plan. You might have more-frequent screening or different screening tests than would someone with an average risk of breast cancer.

Your breast cancer screening may include:

  • Breast self-exams for breast awareness to become familiar with the typical look and feel of your breasts.
  • Clinical breast exams by a healthcare professional once or twice a year.
  • Screening mammograms once a year.
  • Additional breast cancer screening tests based on your other risk factors for breast cancer. These other tests may include breast MRI, molecular breast imaging and other supplemental breast imaging tests. Which test is best for you may depend on your risk factors for breast cancer, your family history of breast cancer, whether you have DNA changes that increase the risk of breast cancer and whether your mammogram images show that you have dense breasts.

Other ways to lower your risk of breast cancer

To reduce your risk of breast cancer, your healthcare team may recommend that you:

  • Avoid hormone therapy for menopause. Certain kinds of medicines that use hormones to help control symptoms of menopause can increase the risk of breast cancer. If you have menopause symptoms, ask your healthcare team about treatments that won't increase your risk of breast cancer.
  • Consider surgery to lower the risk of breast cancer. If you have a very high risk of breast cancer, your healthcare team might recommend surgery to lower your risk. Your risk might be high if you have a strong family history of breast cancer. Your risk also may be high if DNA changes that increase the risk of breast cancer run in your family. One operation that can lower the risk of breast cancer is surgery to remove both breasts. This procedure is called a risk-reducing mastectomy or a prophylactic mastectomy.
  • Make healthy lifestyle choices. Make healthy choices in your daily life to reduce your risk of breast cancer. For instance, exercise most days of the week and maintain a healthy weight. Don't smoke. Limit the amount of alcohol you drink, if you choose to drink alcohol. For breast cancer prevention, there is no safe amount of alcohol. So if you're very concerned about your breast cancer risk, you may choose to not drink alcohol.
  • Participate in a clinical trial. Clinical trials test new treatments. Trials testing the best way to manage the risk of breast cancer in people with atypical hyperplasia may be available. Ask your healthcare team about clinical trials.

Coping and support

Finding out that you have atypical hyperplasia of the breast can feel stressful. Some people say it causes them worry about their risk of breast cancer. With time, you'll find your own way of coping with atypical hyperplasia. Until you find what works for you, consider trying to:

Understand your individual risk of breast cancer

Breast cancer risk statistics can be overwhelming and worrisome. These statistics are figured out by following many people with atypical hyperplasia and monitoring them for breast cancer. While these statistics can give you an idea of your outlook, they can't tell you about your own risk of breast cancer.

Ask your healthcare professional to explain your individual risk of breast cancer. Once you understand your personal risk of breast cancer, you can feel more comfortable making decisions about your treatment.

Go to all of your follow-up appointments

If you've been diagnosed with atypical hyperplasia, you may need more-frequent breast cancer screening exams and tests. It's common to feel anxious or worried before these tests. Don't let these feelings keep you from going to your appointments.

Instead, find activities that help you cope with worries. Relax, write your feelings in a journal or spend time with a close friend who can lift your spirits.

Talk with others in your situation

Connect with others who have been diagnosed with atypical hyperplasia. Ask your healthcare team about support groups in your community and online.

Preparing for an appointment

If a mammogram reveals a suspicious area in your breast, your healthcare professional may refer you to a breast health specialist or a specialized breast center. If you have atypical hyperplasia of the breast, a breast health specialist can help you understand your breast cancer risk and create a plan to help you manage the risk.

What you can do

To prepare for your appointment, try to:

  • Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
  • Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
  • Write down key personal information, including any major stresses or recent life changes.
  • Make a list of all medications, vitamins or supplements that you're taking.
  • Consider taking a family member or friend along. Sometimes it can be difficult to absorb all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.

Questions to ask

Your time with your healthcare team is limited, so prepare a list of questions ahead of time. List your questions from most important to least important in case time runs out. For atypical hyperplasia, some basic questions to ask include:

  • Can you explain my pathology report to me?
  • Do I need more tests?
  • Will I need surgery for atypical hyperplasia?
  • Are there medicines I can take to lower my risk of breast cancer?
  • What can I do to reduce my risk of breast cancer?
  • What symptoms of breast cancer should I watch for?
  • How often should I have a mammogram to screen for breast cancer?
  • Should I also have an MRI to screen for breast cancer?
  • What would you recommend to a friend or family member in my situation?
  • Are there any restrictions that I need to follow?
  • Should I see a breast health specialist? What will that cost, and will my insurance cover it?
  • Should I consider genetic counseling?
  • Are there any brochures or other printed material that I can take with me? What websites do you recommend?

In addition to the questions that you've prepared, don't hesitate to ask other questions that come to mind during your appointment.

What to expect from your doctor

Your healthcare team is likely to ask you a number of questions. Be prepared to answer questions such as:

  • Do you have a family history of breast cancer?
  • Do you have a family history of other types of cancer?
  • Have you had a breast biopsy before? Do you know the results of previous breast biopsies?

Content From Mayo Clinic Updated: 05/28/2024
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