Langer’s Axillary Arch: A Frequently Missed Axillary Anomaly That Can Alter the Outcome of Breast Cancer Management- Case Series

The axillopectoral muscle known as Langer's axillary arch (LAA), is considered the most common anatomical variation of the axilla. The muscular fibers typically originate from latissimus dorsi (LD) muscle, crossing over the axillary neurovascular bundle to insert deep to the insertion of pectoralis major muscle. Although it is frequently missed, surgeons must be attentive to its existence during axillary surgery or LD flap breast reconstruction. LAA fibers should be excised to expose the axillary nodes, vessels and nerves. Failure to identify this anomaly can jeopardize the LD flap vascularity, and can reduce the accuracy of retrieving sentinel lymph nodes, increase the false negative rate, and result in under staging and/or under treatment of the axilla in breast cancer patients. Consequently, altering the decision for adjuvant treatment like chemotherapy or radiation therapy, which would affect the patient’s survival outcome. In the present series, we report 7 cases of the LAA, and describe the surgical findings during axillary surgery for each case, paying special attention to the tips to identifying LAA, its different subtypes, and its clinical implication in breast cancer patients, and summarize existing literature.