A Case of G-CSF-producing Metaplastic Breast Cancer with Chondroid Differentiation

Abstract

A 53-year-old woman presented to the hospital to have a detailed examination and treatment of a 20-cm cancer of the right breast with skin invasion and necrotic ulcer. Distant metastasis was not detected but axillary lymph node metastasis was found. The blood test showed an abnormally high WBC count of 47,200/μL. Although inflammatory findings were scarce, the serum G-CSF was measured to be abnormally high. Chemotherapy was initiated for the locally advanced breast cancer, but it became difficult to continue therapy due to bleeding from the cancer and protein leakage. Therefore, primary cancer resection and lymphadenectomy were performed for local control and quality of life improvement. The pathological findings revealed a metaplastic breast cancer with HER2 protein overexpression and anti-G-CSF antibody-positive chondroid differentiation. G-CSF-producing breast cancer has a high biological malignancy and poor prognosis. This is the first report of G-CSF-producing breast cancer with HER2 overexpression and chondroid differentiation.