A 51-year-old woman presented with a painful sternal lump. Nine years earlier she had undergone right modified mastectomy for breast cancer, followed by chemotherapy. Computed tomography and bone scintigraphy demonstrated a solitary sternal bone metastasis. The patient was treated by partial sternectomy. Thereafter, the sternal defect was reconstructed with Marlex mesh and rectus abdominis myocutaneous flap. The postoperative course was uneventful. The patient subsequently developed brain metastasis and died within 52 months after sternal resection. The stability of the chest wall was well preserved for the duration of follow-up.