Langer's arch: A rare but important consideration for axillary surgery with implications for training.

Langer's arch (LA), although rare, is an important anatomical anomaly in the axilla that may be encountered during axillary lymph node dissection (ALND). Failure to recognize this anomaly may cause disorientation during ALND, resulting in inadequate clearance, with implications for local disease recurrence and inaccurate staging. Here, we present a case that highlights the confusion LA can cause even in experienced surgeons. With indications for ALND decreasing, resulting in lower operative numbers, surgeons are less likely to be exposed to this structure during their training. Improving knowledge and understanding of LA is important to ensure breast surgeons' preparedness for axillary surgery.