Abstract
Malignant tumors that originate from the mesenchymal tissue of the mammary gland, known as breast sarcomas, are very rare and can be divided into 2 types: primary and secondary (therapy-related development). Breast sarcomas are aggressive tumors associated with a poor prognosis. Treatment options include the coordination of surgery, chemotherapy, and radiotherapy. We present a case of a 51-year-old female who presented to the hospital after noticing a palpable mass in the left breast and bloody nipple discharge. These symptoms lasted for more than 4 months. Postoperative histopathology revealed an undifferentiated pleomorphic breast sarcoma. After 8 months of treatment, the patient experienced metastasis to the brain and lungs.