RESUMEN
INTRODUCTION: Contralateral axillary lymph node metastasis (CAM) is a rare clinical condition in patients with breast cancer. It can be explained from hematogenous spread from the original primary tumor (stage IV) to aberrant regional lymphatic drainage to the contralateral axilla. However, according to the current clinical guidelines, regardless of its origin, CAM is considered as metastatic disease. CASE PRESENTATION: A 68-year-old woman presented with relapsed right breast cancer; lymphoscintigraphy showed only one sentinel lymph node (SLN) in the contralateral axilla (left region). Twenty-four hours later, the patient underwent upper internal quadrantectomy and bilateral selective lymph node biopsy. The final pathological analysis revealed one contralateral macrometastasis (>4 mm) in one left SLN. Subsequently, second-level left lymphadenectomy was performed. Currently the patient is being treated with chemotherapy, with appropriate clinical response. DISCUSSION: Our patient was considered to be node-positive rather than having metastatic disease since the preoperative lymphoscintigraphy demonstrated contralateral lymphatic drainage. Through preoperative scan in patients with relapsed breast cancer with clinically negative lymph nodes and CAM, it is possible to identify those cases that would benefit from therapy with curative intention.