[A case of a patient with breast cancer, diagnosed from sternal metastasis]

A 32-year-old woman was seen in our hospital for complaints of bulge and pain in the sternum, and upon examination showed a lump in the left breast and enlarged left axillary lymph nodes. The patient was diagnosed with invasive ductal carcinoma with metastasis to the sternum that was T2N1M1(OSS), Stage IV, hormone-receptor-positive, and HER2-negative. Four courses each of EC and taxane therapy were performed as primary systemic chemotherapy in combination with zoledronic acid, which resulted in calcification of the osteolytic lesion in the sternum and reduced tumor mass in the breast. The patient was judged to have a partial response(PR)to the treatment. Eight months later, breast-conserving surgery and axillary lymph node dissection were performed, followed by radiation therapy to the left breast and sternum. Treatment with zoledronicac id is ongoing and postoperative hormonal therapy has been started. Four years and 4 months after the initial diagnosis, the lesion in the sternum has calcified and hardened and the patient has not had a recurrence in the same breast or elsewhere in the body.