Management of atypical lobular hyperplasia, atypical ductal hyperplasia, and lobular carcinoma in situ

SUMMARY

Atypical hyperplasia and lobular carcinoma in situ are rare proliferative breast lesions, growing inside ducts and terminal ducto-lobular units. They represent a marker of increased risk for breast cancer and a non-obligate precursor of malignancy. Evidence available on diagnosis and management is scarce. They are frequently found incidentally associated with other lesions, but can be visible through mammography, ultrasound or magnetic resonance. Due to the risk of underestimation, surgical excision is often performed. The analysis of imaging and histopathological characteristics could help identifying low-risk cases, for which surgery is not necessary. Chemopreventive agents can be used for risk reduction. Careful imaging follow up is mandatory; the role of breast MRI as screening modality is under discussion.

KEYWORDS:

• Breast
• atypical hyperplasia
• lobular neoplasms
• intraductal carcinoma
• image guided biopsy
• screening
• chemoprevention
• mammography
• magnetic resonance imaging
• case management

Financial and competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Key issues

• AH and lobular neoplasms are rare proliferating breast lesions, often found in association with other histopathological entities, both benign and malignant.

• ADH, ALH, and LCIS are associated with an increased risk of developing breast cancer, in both the ipsilateral and contralateral breast, and are proven non-obligate precursor of malignant breast lesions.

• They are usually visible on imaging as microcalcifications on mammography, but they can also present as masses on mammography and ultrasound or as areas of non-mass enhancement on breast magnetic resonance.

• The upgrade rate to malignancy at surgical excision ranges from lower than 2% to higher than 40%, being lower for ALH and higher for ADH and for non-classical LCIS subtypes.

• Available evidence comes almost entirely from retrospective studies with a small number of cases, and thus present several significant limitations. For these reasons, the diagnostic, therapeutic, and follow-up strategies for these patients are still subject to intense discussion.

• Recent studies suggest that the careful evaluation of both imaging findings and histological characteristics at biopsy specimen can be used to safely exclude associated malignancy. When these markers of low risk are used, it is possible to identify a group of patients who will most likely not benefit from surgical excision.

• Prospective multicentric studies are necessary to confirm the possibility of avoiding surgical excision in selected cases.

• Owing to the increased risk of cancer associated with ADH and LN, careful and regular follow-up is mandatory. MRI should be considered as a screening tool in these patients.