Clinical Report: Malignant Adenomyoepithelioma in the Breast with Challenges

Background

Malignant adenomyoepithelioma is a rare biphasic breast neoplasm. Accurate preoperative diagnosis is challenging due to the limitations of core needle biopsy, which may not adequately sample the tumor's malignant features. Understanding the histologic characteristics and management strategies for MAME is crucial.

Data Highlights

No numerical or trial data available in the source material.

Key Findings

• Malignant adenomyoepithelioma (MAME) is characterized by biphasic epithelial and myoepithelial components.
• Core needle biopsy (CNB) may lead to misdiagnosis, as seen in this case where it suggested invasive carcinoma of no special type.
• Final pathology confirmed grade 3 malignant MAME with perineural invasion and a Ki-67 proliferation index of 20%.
• Negative-margin resection is essential in the management of MAME, with lymph node involvement being uncommon.
• Adjuvant therapy may be necessary, and patients require prolonged surveillance for late recurrence.

Clinical Implications

Clinicians should be aware of the diagnostic pitfalls associated with MAME, particularly the limitations of core needle biopsy.

Conclusion

This case highlights the importance of recognizing histologic-subtype discordance in malignant adenomyoepithelioma, which poses unique diagnostic challenges.

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