Seven years ago, a 48-year-old female patient discovered a painless tumor in her right breast simply by chance. In the next year, the tumor increased significantly in size. At this point, the patient received a tumor resection, which was misdiagnosed as a benign mesenchymal tissue-originated tumor. Unfortunately, the tumor recurred just 10 days after resection. We subsequently resected the recurrent lesion and confirmed primary breast malignant fibrous histiocytoma. The tumor began to exhibit an unprecedented, massive, and uncontrolled growth, ulcerating soon after the operation. Treatment of the patient was limited by time. After the patient received a cycle of chemotherapy, she died of cachexia with the emergence of multiorgan metastasis 2 months after the operation.