[Bone Marrow Metastases of Breast Cancer Treated with Endocrine Therapy-A Case Report].

We report a case of bone marrowmetastases of breast cancer treated with endocrine therapy. A 54-year-old woman underwent right partial mastectomy and sentinel lymph node biopsy, followed by adjuvant chemotherapy and radiotherapy. She declined the endocrine therapy and was lost to follow-up after 3 postoperative years. After 9 postoperative years, she visited our hospital because of backache and an axillary lump. FDG-PET scan, incisional biopsy of the axillary lump, and bone marrowbiopsy revealed multiple bone and bone marrowmetastases of the breast cancer. She was treated with endocrine therapy(fulvestrant: FUL), which effectively decreased the FDG uptake in the metastatic lesions after 6 months. However, tumor markers elevated after 1 year and 6 months, and she is currently under combination therapy with aromatase inhibitors and CDK4/6 inhibitors.