[Case of Spindle Cell Carcinoma of the Breast Resistant Neoadjuvant Chemotherapy].

We report a rare case of spindle cell carcinoma of the breast which grew rapidly during neoadjuvant chemotherapy. A 72- year-old female was presenting with chief complaint of a mass in the right breast; a tumor about 20 mm in size. Core needle biopsy of tumor revealed invasive ductal carcinoma and fine needle aspiration cytology of axillary lymph node was Class Ⅴ. So she was diagnosis breast cancer as cT2N1M0, cStage ⅡB. The tumor subtype was triple negative breast cancer (TNBC). She received the neoadjuvant chemotherapy by FEC100. After FEC 4 courses, we detected a huge and rapid growing breast mass of 40 mm by CT. She was administered received mastectomy and axillary lymph node dissection after 4 months from initial contact. Pathological finding was spindle cell carcinoma of the breast. Postoperatively, she was treated with weekly PTX for a total of 12 courses and radiation therapy for a right chest wall and supraclavicular fossa. Although the tumor was resistant for neoadjuvant chemotherapy, she is alive and well without metastasis for more than 3 years.