Contralateral axillary lymph node and chest wall skin recurrence 2 years after radical mastectomy for breast cancer: a case report and literature review.

[BACKGROUND] Contralateral axillary lymph node metastasis (CAM) following radical mastectomy for breast cancer is a rare and clinically challenging event, with a reported incidence of approximately 1.9% to 6.0%. Its pathogenesis, often attributed to altered lymphatic drainage after primary breast surgery, is not fully elucidated. The classification of CAM remains controversial, as current American Joint Committee on Cancer (AJCC) staging guidelines categorize it as distant metastasis (M1), while emerging clinical evidence suggests its biological behavior and prognosis may align more closely with advanced regional (stage III) disease. This ambiguity complicates management, as standardized treatment guidelines are lacking. Accurate diagnosis is imperative and requires thorough investigation to exclude a new occult primary malignancy or metastases from other tumors.

[CASE DESCRIPTION] We report a detailed case of a 39-year-old female who developed synchronous CAM and extensive contralateral chest wall skin involvement, presenting as nodules and ulceration, 2 years after undergoing a right modified radical mastectomy for triple-negative breast cancer. Despite undergoing multiple lines of systemic therapy over several years, the disease progressed locally at these contralateral sites without evidence of other distant metastases. After comprehensive imaging and histopathological evaluation confirmed the metastatic origin from her primary breast cancer, the patient underwent aggressive local surgical resection. This included a left radical mastectomy with nipple-areola complex preservation, wide resection of the chest wall tumor, and immediate reconstruction using a pedicled latissimus dorsi flap. The patient tolerated the procedure well, achieved clear margins, and had a satisfactory postoperative recovery.

[CONCLUSIONS] CAM represents a complex clinical scenario that necessitates meticulous differential diagnosis and multimodal evaluation. The outcome of this case, alongside a review of the literature, suggests that in selected patients without concomitant distant metastases, CAM may behave as a locoregional progression rather than systemic dissemination. Therefore, a blanket classification as stage IV disease may lead to the undertreatment of potentially curable local recurrences. Current evidence supports considering an aggressive local therapeutic approach, including surgery and/or radiotherapy, combined with systemic therapy to enhance local control and improve prognosis. An individualized, comprehensive treatment strategy is strongly recommended to optimize survival outcomes in such rare cases.