Fibromatosis-Like Metaplastic Carcinoma: A Triple-Negative Breast Cancer with Clinically Indolent Behavior

Fibromatosis-like metaplastic carcinoma is a special variant of spindle cell carcinoma, a type of metaplastic carcinomas. It has a favorable prognosis, unlike other metaplastic carcinomas, with a particular clinical behavior characterized by frequent local recurrence, the meager potential for axillary lymph nodes, and distant metastases. We presented the case of a 51-year-old female with a large mass on the left breast, which was successfully removed by surgical resection. The pathological diagnosis was fibromatosis-like metaplastic carcinoma with the help of morphology and immunohistochemistry adjustment.