A Case of Bone Marrow Carcinomatosis of Occult Breast Cancer Treated Effectively with Fulvestrant

: A 63-year-old woman experienced left cervical lymph node swelling since May 2012. Based on PET-CT findings, metastases of a malignant tumor to the mediastinal, axillary, and left cervical lymph nodes were suspected. Her left cervical lymph node biopsy revealed metastatic carcinoma of occult cancer, because no primary tumor could be identified despite the specific examinations. She rejected further therapeutic intervention. In July 2013, she was admitted because of anemia, cardiac failure, and fever. She was diagnosed with bone marrow carcinomatosis from occult cancer based on her bone marrow biopsy. Metastatic breast cancer was mostly considered because she tested positive for estrogen and progesterone receptors, CA15-3 levels were increased, and her axillary lymph nodes were swollen. Fulvestrant and zoledronic acid were administered and continued for 20 months, with improvement in anemia and tumor marker levels, and also maintenance of partial response.