[A Case of Breast Cancer with Parenchymal and Meningeal Central Nervous System Metastases Treated with Multimodality Therapy].

A 64-year-old woman who received neo-adjuvant chemotherapy and human epidermal growth factor receptor 2(HER2)- targeted therapy underwent modified radical mastectomy and axillary lymph node resection for HER2-positiveright breast cancer. After the surgery, chemotherapy, post-mastectomy radiation therapy, and HER2-targeted therapy were administered as adjuvant therapies. Two years and 6 months postoperatively, she complained of headaches and nausea. Magnetic resonance imaging showed brain metastasis, which was treated with gamma knife surgery. Two weeks later, she was urgently admitted to the hospital because of impaired consciousness. Based on cerebrospinal fluid cytology, she was diagnosed with meningeal metastasis of breast cancer. She developed hydrocephalus; thus, external ventricular drainage was performed, and a ventriculoperitoneal shunt was inserted. She was treated with whole-brain irradiation(30 Gy)and trastuzumab emtansine (T-DM1)as systemic therapy. Treatment of the patient was possible without recurrence continuously for over 12 months and with the maintenance of daily activities. The prognosis of patients with meningeal metastasis of breast cancer is extremely poor, and effective pharmacotherapy has not yet been established. T-DM1 may improvepatie nts' quality of lifeand the clinical outcomes of meningeal metastasis.