Breast cancer metastasizing to the contralateral axilla several years after treatment: A case report with literature review

INTRODUCTION AND IMPORTANCE: Lymph node metastasis is the most prominent prognostic factor in breast cancer. The aim of this paper is to report a case of contralateral axillary lymph node metastasis (CAM) which look like metachronous initially, but histopathologicaly confirmed as synchronous CAM. CASE PRESENTATION: A-44-year old female was a known case of left breast cancer five years prior to this presentation (T2,N2,M0, grade III, Triple negative, multifocal invasive ductal carcinoma). On follow up, multiple contralateral axillary suspicious lymph nodes were discovered. Fine Needle Aspiration Cytology from the lesion revealed grade III, Triple negative, invasive ductal carcinoma consistent with metastasis from the left invasive ductal carcinoma. Bilateral mastectomy and right axillary dissection were performed. The histopathological examination and immunohistochemistry showed left breast recurrent 0.5 cm grade III, Triple negative invasive ductal carcinoma. DISCUSSION: If a cancer is found in the contralateral axilla, three main potential sources should be considered: contralateral spread from the original breast tumor, metastasis from an occult primary in the ipsilateral breast, and metastasis from an extramammary site. CONCLUSION: Although CAM in patients with breast cancer is an uncommon condition, it is still possible to occur. There is a controversy regarding the appropriate management.