Mammary hyperplasia refers to a non-cancerous condition where there is an increase in the number of cells lining the milk-producing glands (lobules) or milk ducts within the breast. This cellular overgrowth is a benign finding, not breast cancer itself. It represents a common change in breast tissue.
Types of Mammary Hyperplasia
Mammary hyperplasia is categorized based on how the cells appear under a microscope, with two main classifications: usual ductal hyperplasia (UDH) and atypical hyperplasia. Usual ductal hyperplasia involves an overgrowth of cells that appear close to normal. These proliferating cells fill and distend the ducts and lobules, but they do not exhibit abnormal patterns or shapes.
Atypical hyperplasia involves cells that look more distorted and abnormal. This type is further divided into atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia (ALH). ADH involves abnormal cells within the breast ducts, which are tubes that carry milk to the nipple. ALH describes the growth of atypical cells within the breast lobules, the glands responsible for milk production.
In ADH, cells grow in an irregular pattern and possess some characteristics of ductal carcinoma in situ (DCIS), an early-stage breast cancer, though it is not DCIS itself. ALH involves abnormal cell growth within the lobules. Both ADH and ALH carry comparable risks of future breast cancer.
How Mammary Hyperplasia is Diagnosed
Mammary hyperplasia often does not cause noticeable symptoms like a palpable lump and is frequently discovered incidentally. It may present as changes visible on a mammogram, such as microcalcifications or densities. These microcalcifications are small calcium deposits that can be present in both non-cancerous and cancerous breast lesions.
When imaging findings suggest an abnormality, a biopsy is typically performed for a definitive diagnosis. This involves removing a sample of the abnormal breast tissue, often through a core needle biopsy or, less commonly, an excisional biopsy. A pathologist then examines this tissue under a microscope to determine the specific type of hyperplasia. Ultrasound and MRI may also be used in the diagnostic process.
Understanding the Link to Breast Cancer
While mammary hyperplasia itself is a benign condition, certain types are recognized as risk factors for developing invasive breast cancer in the future. Usual ductal hyperplasia (UDH) carries a slightly increased risk, approximately 1.5 to 2 times higher than that of women without breast abnormalities. This risk is generally considered small, and UDH usually does not require specific treatment or follow-up beyond routine screenings.
Atypical hyperplasia poses a more significant increased risk for future breast cancer. Women with atypical hyperplasia have about a 3 to 5 times higher risk of developing breast cancer. This elevated risk is similar for both ADH and ALH. Atypical hyperplasia is thought to be a very early step in the process that can lead to cancer, though it is not pre-cancer or cancer itself. Studies indicate that the risk of breast cancer in individuals with atypical hyperplasia increases over time.
Management and Monitoring of Mammary Hyperplasia
The management and monitoring strategies for mammary hyperplasia depend on the specific type identified. For usual ductal hyperplasia, no specific treatment is typically required beyond routine breast health screenings. It is still important for individuals to be aware of their breast health and report any new changes to their healthcare provider.
For atypical hyperplasia (ADH and ALH), enhanced surveillance is generally recommended due to the increased breast cancer risk. This often includes annual mammograms and clinical breast examinations every 6 to 12 months. Additional imaging modalities like breast MRI may also be considered.
In cases where atypical hyperplasia is found on a core needle biopsy, surgical excision of the area may be recommended to ensure no more serious lesions, such as DCIS or invasive cancer, are present. If only atypical hyperplasia is found after surgical removal, further treatment is often not needed. Lifestyle modifications, such as maintaining a healthy diet and regular exercise, can also contribute to overall breast health and may be discussed as part of a comprehensive management plan. In some high-risk situations, risk-reducing medications, like selective estrogen-receptor modulators (SERMs) or aromatase inhibitors (AIs), might be considered.