Primary ectopic axillary breast cancer: a case series

Introduction: Ectopic breast tissue is present in 2-6% of women. Ectopic breast cancer represents an uncommon disease accounting for about 0.3% of all breast neoplasms, limiting the available evidence. Thus, we aim to report long-term outcomes in five cases treated at our institution.

Case series: Our Tunisian patients' median age was 48 years (33-60 years), and the median follow-up was 8 years (4-10 years). The ectopic breast tissue was located four times in the right axilla. The median tumor size was 25 mm (15-55 mm). Four of the patients underwent a wide local excision and axillary lymph node dissection. Three of those women had positive lymph nodes; thus, they received adjuvant chemotherapy, radiation therapy, and hormone therapy. The patient with a negative lymph node (case 5) had adjuvant radiation therapy and hormonal therapy. One of the patients (case 1) had a positive supraclavicular lymph node and received radiation therapy, chemotherapy, and hormonal therapy. The latter developed a locoregional relapse after 4 years and was treated with mastectomy and chemotherapy. One patient (case 4) had a distant metastasis after 2 years of follow-up and received chemotherapy. The three other patients were free of relapse during their follow-up period.

Conclusion: Primary axillary breast carcinoma is a rare entity. Despite the paucity of literature, our findings and authors' recommendations suggest that local excision can be performed safely with promising outcomes in this subset of patients.