A 52-year-old woman diagnosed at our hospital with breast cancer (ER−/PgR−/HER2−) with lymph node and bone metastasis was given systemic chemotherapy with epirubicin plus cyclophosphamide and zoledronic acid. This proved ineffective, so breast-conserving surgery with axillary lymph node dissection was performed for the purpose of local control and pathological evaluation. The pathological therapeutic effect was classified as grade 1, and the endocrine receptor status changed to positive. After surgery, the patient received chemotherapy with docetaxel plus cyclophosphamide twice and paclitaxel twice. Endocrine therapy was subsequently administered. One month after the start of endocrine therapy, the patient experienced pain throughout her body and fatigue, and a blood test showed thrombocytopenia. A bone marrow biopsy led to a diagnosis of disseminated carcinomatosis of the bone marrow resulting from metastatic breast cancer. Her symptoms did not improve even after hospital treatment, and she died 6 months after the breast surgery. This case of breast cancer resulting in rapid death from disseminated intravascular coagulation (DIC) caused by disseminated carcinomatosis of the bone marrow illustrates the urgent need for further consideration of the risk factors for this disease and determination of optimal therapy.
