Right breast cancer with contralateral axillary lymph-node metastasis

What happened, in summary

A 61-year-old woman sought care for a right breast lump that she had noticed for three months. Examination found a hard mass in the right lower outer breast and enlarged lymph nodes in both axillae, although no left-breast mass was palpable. Imaging and tissue assessment did not identify a separate primary cancer in the left breast or disease outside the breast and axillary regions.

She underwent bilateral modified radical mastectomy with bilateral axillary dissection. The right breast contained a 2 to 3 cm grade 1 invasive ductal carcinoma. One of 26 right axillary nodes and three intramammary nodes contained cancer. All 16 removed left axillary nodes also contained metastatic carcinoma, while the left breast showed only fibrocystic changes. The right primary was ER-positive, PR-positive, HER2-negative, and had a Ki-67 index of 70%. The left axillary metastasis was ER-positive, PR-negative, HER2-negative, GATA3-positive, and had a Ki-67 index of 15%.

Her synchronous contralateral axillary spread was classified as stage IV disease. She recovered without postoperative complications and was referred to oncology for adjuvant chemotherapy. She continued clinical and radiological follow-up every six months. Two years after surgery, there was no evidence of metastasis or recurrence.