Ectopic Breast Tissue and Associated Malignancies
Summary
Ectopic breast tissue comprises aberrant mammary glands located along the embryonic mammary ridge, extending from the axilla to the groin. Although present in an estimated 2–6% of the population, it often remains undetected until pathological changes arise. Supernumerary breasts and accessory mammary glands share the capacity for the full spectrum of breast pathologies, including benign lesions such as fibroadenomas and rare malignant transformations. Malignancies in ectopic tissue most commonly present as invasive ductal carcinomas, mirroring orthotopic breast cancers in histological features and receptor profiles. Clinical challenge stems from atypical location outside routine imaging fields, leading to diagnostic delays. Management parallels standard breast oncology, encompassing surgical excision with clear margins, evaluation of regional lymph nodes, and systemic therapies guided by hormone receptor and HER2 status. Emerging evidence emphasises the need for heightened awareness among clinicians, the role of imaging modalities in detection, and tailored reconstructive approaches given unique anatomical constraints.
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Ectopic Breast Tissue and Associated Malignancies publication trend
The graph below shows the total number of articles in ectopic breast tissue and associated malignancies across all publications each year (not limited to Nature Index journals).
Technical terms
Ectopic breast tissue: Mammary tissue located outside the normal breast area along the embryonic milk line.
Accessory breast cancer: Malignant transformation arising within ectopic mammary glands or supernumerary breast tissue.
Milk line: Embryonic ridge extending from axilla to groin, along which breast tissue can develop.
Neoadjuvant therapy: Treatment administered before primary surgery to reduce tumour burden.
Adjuvant therapy: Systemic or local treatment given after surgical excision to eliminate residual disease.
Sentinel lymph node biopsy: Targeted removal of the first lymph node(s) draining a tumour to assess metastatic spread.
References
- Primary ectopic axillary breast cancer: a case series. Journal of Medical Case Reports (2021).
- Locally advanced breast cancer arising in the axilla. Journal of Surgical Case Reports (2022).
- Accessory breast cancer in the inframammary region: a case report and review of the literature. Surgical Case Reports (2021).
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