Contralateral Axillary Lymph Node Metastasis in Breast Cancer, an Unusual Clinical Scenario: A Case Report and Review of the Literature

<p><strong>Background:</strong> Contralateral axillary metastasis (CAM) is a rare entity in patients with breast cancer which can occur during the primary breast cancer or its follow-up. Different treatment modalities include surgery, radiotherapy, and chemotherapy, but there is no agreement on them. In our review, we found 12 series with available data, 82 patients with synchronous or metachronous contralateral axillary node involvement with no primary cancer in the contralateral breast. </p><p><strong>Case Presentation:</strong> Our patient was a 50-year-old woman who presented with locally advanced right breast cancer with no distant metastasis. After treatment including neoadjuvant chemotherapy, MRM, and radiotherapy, her contralateral axillary lymph node was involved with metastatic carcinoma compatible with ductal carcinoma of the breast with similar IHC results. Evaluation of the contralateral breast was negative for occult lesions and metastatic workups were negative for malignancy. We assumed this presentation as a CAM and planned the treatment accordingly.</p><p><strong>Conclusion:</strong> CAM without systemic metastasis might be considered a regional disease because in many cases the spread is lymphatic and not hematogenous. The new concept of lymphatic invasion instead of hematogenous spread has changed the intent of palliative to curative treatment. According to our study, CAM patients were mostly managed with chemotherapy (96%), ALND (45%), contralateral breast and axillary radiation (35%). The prognosis of CAM is usually poor with a high relapse rate (&gt;60%) and a mortality rate of 15% in our review after 14-43 months follow-up, but it is better than the prognosis of the patients with systemic metastasis.