[A Case of Mastectomy and Axillary Lymph Node Dissection for Breast Cancer on the Side of Pacemaker Implant].

The patient was a woman in her 80s with a history of atrial fibrillation at age 80, and catheter ablation and pacemaker implantation for sinus bradycardia. Her chief complaint is a left lateral breast mass. A pacemaker was implanted subcutaneously in the caudal left subclavian region, and palpation revealed a 20 mm-sized elastic hard mass in the left D area. On close examination, she was diagnosed as HER2-enriched invasive ductal carcinoma of the breast, T1cN0M0, cStage Ⅰ. The surrounding fatty tissue was preserved without exposing the pacemaker, and a subtotal left breast resection plus sentinel lymph node biopsy was performed, with additional axillary lymph node dissection due to positive metastasis. Intraoperative pacemaker monitoring was performed and no trouble was observed. The patient was discharged on the 6th postoperative day without complications. Pathology results showed pT2pN2aM0(7/16), pStage ⅢA. Postoperatively, the patient is scheduled to receive radiation to the chest wall without a pacemaker and chemotherapy.