Atypical hyperplasia is a precancerous condition that affects cells in the breast. Atypical hyperplasia describes an accumulation of abnormal cells in a breast duct (atypical ductal hyperplasia) or lobule (atypical lobular hyperplasia).
Atypical hyperplasia isn’t cancer, but it can be a forerunner to the development of breast cancer. Over the course of your lifetime, if the atypical hyperplasia cells keep dividing and become more abnormal, your condition may be reclassified as noninvasive breast cancer (carcinoma in situ) or breast cancer.
If you’ve been diagnosed with atypical hyperplasia, you have an increased risk of developing breast cancer in the future. For this reason, doctors sometimes recommend more frequent breast cancer screening and careful consideration of medications and other strategies to reduce breast cancer risk.
Atypical hyperplasia doesn’t cause any specific signs or symptoms.
When to see a doctor
Make an appointment with your doctor if you have any signs or symptoms that worry you.
Atypical hyperplasia doesn’t cause signs and symptoms, but it’s usually discovered during a breast biopsy to investigate breast signs and symptoms caused by another condition or an abnormality found on a mammogram.
It’s not clear what causes atypical hyperplasia. Atypical hyperplasia forms when breast cells become abnormal in number, size, shape, growth pattern and appearance. Location of the abnormal cells within the breast tissue — the lobules or the milk ducts — determines whether the cells are atypical lobular hyperplasia or atypical ductal hyperplasia.
Atypical hyperplasia is thought to be part of the complex, multistep process by which breast cancer develops. The process begins when normal cell development and growth become disrupted, causing an overproduction of normal-looking cells (hyperplasia). Atypical hyperplasia occurs when the excess cells stack upon one another and begin to take on an abnormal appearance. The abnormal cells can continue to change in appearance and multiply, evolving into noninvasive (in situ) cancer, in which cancer cells remain confined to the area where they start growing. Left untreated, the cancer cells may eventually become invasive cancer, invading surrounding tissue, blood vessels or lymph channels.
Increased risk of breast cancer
If you’ve been diagnosed with atypical hyperplasia, you have an increased risk of breast cancer in the future. Women with atypical hyperplasia have a risk of breast cancer that is about four times higher than that of women who don’t have atypical hyperplasia.
Being diagnosed with atypical hyperplasia at a younger age may increase the risk of breast cancer even more. Women diagnosed with atypical hyperplasia before age 45 have a greater risk of developing invasive breast cancer during their lifetimes, compared with older women, especially those older than 55.
If a mammogram reveals a suspicious area in your breast, your doctor may refer you to a breast health specialist or a specialized breast center.
What you can do
Because appointments can be brief, and because there’s often a lot of ground to cover, it’s a good idea to be well prepared. To prepare for your appointment, try to:
Questions to ask
Your time with your doctor 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 your doctor include:
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 doctor is likely to ask you a number of questions. Being ready to answer them may allow more time later to cover other points you want to address. Your doctor may ask:
Atypical hyperplasia is usually discovered after a biopsy to evaluate a suspicious area found on a mammogram or during a clinical breast exam. During the biopsy, tissue samples are removed and sent for analysis by a specially trained doctor (pathologist). The tissue samples are examined under a microscope, and the pathologist identifies atypical hyperplasia, if it’s present.
To further evaluate atypical hyperplasia, your doctor may recommend surgery to remove a larger sample of tissue to look for breast cancer. A diagnosis of atypical hyperplasia may lead to a surgical biopsy (wide local excision or lumpectomy) to remove all of the affected tissue. The pathologist looks at the larger specimen for evidence of in situ or invasive cancer.
Atypical hyperplasia is generally treated with surgery to remove the abnormal cells and to make sure no in situ or invasive cancer also is present in the area. Doctors often recommend more frequent screening for breast cancer and strategies to reduce your breast cancer risk.
Follow-up tests to monitor for breast cancer
Your doctor may recommend you undergo follow-up tests to screen for breast cancer. This may increase the chance that breast cancer is detected early, when a cure is more likely. Talk about your breast cancer screening options with your doctor. Your options may include:
Ways to reduce your risk of breast cancer
To reduce your risk of developing breast cancer, your doctor may recommend that you:
But this surgery isn’t right for everyone. Discuss with your doctor the risks, benefits and limitations of this risk-reducing surgery in light of your personal circumstances. If you have a strong family history of breast cancer, you might benefit from also meeting with a genetic counselor to evaluate your risk of carrying a genetic mutation and the role of genetic testing in your situation.
An atypical hyperplasia diagnosis can be stressful, since it increases your risk of breast cancer. Not knowing what the future holds may make you fearful for your health. With time, every woman develops her own way of coping with atypical hyperplasia and her increased risk of breast cancer. Until you find your way of coping, consider trying to: