A 49-year-old woman was admitted to our hospital because of a tumor in her right breast. The tumor was localized to the C area and was approximately 3 cm in size. A right axillary lymphadenopathy was also found. Histopathological examination and needle biopsy of the breast tumor revealed invasive lobular carcinoma, and she was diagnosed with Stage ⅡB triple-negative breast cancer(cT2N1M0). Paclitaxel plus bevacizumab chemotherapy followed by ddAC chemotherapy was administered as neoadjuvant chemotherapy, but the tumor remained stable. Thus, she underwent mastectomy and lymph node dissection. Pathological findings of the resected specimen showed invasive carcinoma with cartilaginous differentiation. She was then treated with capecitabine 15 days after the surgery; however, multiple lung metastases were found on CT after 6 courses. Therefore, she was transferred to another hospital and received other chemotherapies, but died after 5 months.