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Atypical Hyperplasia of the Breast: Follow-up and Management


Atypical hyperplasia of the breast is a benign but high-risk condition that can be either ductal (ADH) or lobular (ALH); these occur with equal frequency and together are found in about 10% of breast biopsies. Either entity confers a long-term risk of breast cancer that approaches 30% at 25 years of follow-up.

  • Surgically excise atypical hyperplasia when found on a core-needle biopsy
    • Necessary to avoid missing invasive cancer due to sampling error
    • DCIS or invasive cancer found in 10 to 20% of cases
  • Exception: Clinical and radiologic follow-up appropriate when atypical hyperplasia is an incidental finding at the site of a targeted biopsy
  • Current breast cancer risk assessment models perform poorly among women with atypical hyperplasia
    • Atypical hyperplasia associated with a relative risk of approximately 4 for future breast cancer
  • Follow-up screening recommendations include annual mammography, breast awareness, and  clinical encounter every 6 to 12 months
    • Also consider
      • Tomosynthesis
      • Annual MRI to begin at diagnosis
    • Based on emerging evidence, ACOG also recommends consideration of yearly breast MRI for atypical hyperplasia
  • Encourage pharmacologic risk reduction with either a selective estrogen-receptor modulator (SERM) or an aromatase inhibitor (AI) for prevention of breast cancer
  • Counsel about healthy lifestyle including ideal body weight and alcohol reduction
  • Atypical hyperplasia is generally not an indication for surgical risk-reduction / mastectomy


Atypical hyperplasia of the breast reflects proliferation of dysplastic epithelial cell populations.  It is felt to be a transitional zone between benign and malignant breast disease, containing some but not all features of a cancer. Although statistically the long-term risk of breast cancer equals or exceeds that conferred by family history and other risk factors, current guidelines in screening do not reflect this.  Similarly, pharmacologic risk reduction strategies have been adopted by <1% of women who could potentially benefit from them.


  • Atypical lobular hyperplasia is histologically similar to lobular carcinoma in situ, but less extensive
  • Atypical ductal hyperplasia and ductal carcinoma in situ share histologic features
  • Both types of hyperplasia share molecular characteristics and gene expression, indicating possibly a continuum of abnormalities

Learn More – Primary Sources:

Atypical Hyperplasia of the Breast—Risk Assessment and Management Options

Understanding the premalignant potential of atypical hyperplasia through its natural history: a longitudinal cohort study

National Comprehensive Cancer Network. Breast cancer screening and diagnosis.

ACOG: Diagnosis and Management of Benign Breast Disorders