The clavipectoral fascia as the unique anatomical criteria for distinguishing breast parenchymal lesions from axillary lymph node metastasis

Diagnosing primary breast tumors of the axillary tail of Spence may be extremely challenging, since several lesions may be located in the axillary fossa. In the presented case, a 54-year-old post-menopausal Caucasian female patient presented to our institution complaining about a lump in her left axilla. The preoperative imaging modalities could not clarify whether the tumor is part of the tail of Spence or metastasis of the axillary lymph nodes. The diagnosis of primary adenocarcinoma of the axillary tail of Spence was made during a quadrantectomy of the left breast after the clavipectoral fascia, which constitutes the sole anatomical boundary between breast and axilla, was identified.