Anatomical Variation of the Thoracodorsal Nerve in Extensive Axillary Disease: A Case Report

The thoracodorsal nerve (TDN) is an important anatomical landmark to identify and preserve during axillary surgery. We report a rare case of aberrant TDN anatomy in a 55-year-old female undergoing axillary lymph node dissection (ALND) for locally advanced left breast cancer. Intraoperatively, the TDN was not in its expected position in the axilla and, once identified, was observed passing posterior to the thoracodorsal vascular pedicle. The nerve was separated posteriorly from the vascular pedicle by a large nodal mass and remained posterior until entering latissimus dorsi (LD). This report discusses the current understanding of TDN variants and implications for misidentifying or injuring the TDN during axillary surgery. Understanding these variants is especially important in the climate of de-escalation of surgical management of the axilla in breast cancer.