Ectopic breast tissue in axillary lymph node

Area of Science:

• Pathology
• Radiology
• Oncology

Background:

• Benign epithelial inclusions in lymph nodes are rare, with ectopic breast tissue in axillary lymph nodes being particularly uncommon.
• A history of nipple adenoma may be associated with ectopic breast tissue.
• Mammography and sentinel lymph node biopsy are increasingly used, potentially leading to more frequent detection of such incidental findings.

Observation:

• A 48-year-old woman presented with a swollen left axillary lymph node showing amorphous calcifications on mammogram.
• Fine needle aspiration cytology revealed only cystic changes.
• Excisional biopsy confirmed benign mammary epithelial and glandular inclusions within the lymph node.

Findings:

• Microscopic examination definitively identified benign ectopic breast tissue within the axillary lymph node.
• No evidence of malignancy was found in the examined lymph node.
• The findings highlight the importance of distinguishing benign inclusions from neoplastic processes.

Implications:

• Increased detection of ectopic breast tissue in lymph nodes is anticipated due to widespread mammography screening and sentinel lymph node biopsies.
• Ectopic breast tissue in lymph nodes can mimic malignant lesions, necessitating careful histopathological evaluation.
• Accurate identification of benign epithelial inclusions is crucial to avoid misdiagnosis and unnecessary treatment for breast cancer.