Successful chemo-endocrine therapy for multiple bone metastases and myelophthisis caused by occult breast carcinoma

We report a 55-year-old postmenopausal woman with occult breast carcinoma with multiple bone metastases and myelophthisis in whom complete response (CR) was achieved with chemo-endocrine therapy. At the time of admission, she had anemia and left axillary lymph node enlargement, with extremely high levels of serum tumor markers and no breast mass on physical examination or on a mammogram. Roentgenograms and bone scintigrams showed multiple bone, lung, and pleural metastases. Bone marrow biopsy and aspiration cytology from the left axillary lymph node revealed an invasion of adenocarcinoma cells. On immunohistochemical staining, the cancer cells were positive for estrogen receptor (ER), progesterone receptor (PgR), and gross cystic disease fluid protein-15 (GCDFP-15). CR was induced with a combination chemotherapy of doxorubicin, cyclophosphamide, and 5-fluorouracil (CAF), and has been maintained with sequential docetaxel administration with endocrine therapy. Her performance status (Eastern Cooperative Oncology Group) improved from 4 to 0. This patient represents a very specific and rare case in whom a primary tumor could not be detected despite severe advanced breast carcinoma, and in whom CR was achieved by chemo-endocrine therapy.