RESUMO
Metaplastic breast cancer (MBC) comprises less than 1% of all breast cancers, and it is defined by a mixture of adenocarcinoma plus mesenchymal and epithelial components. It is more common in older and black female patients. It has a larger size and faster growth, and it is frequently node-negative and triple-negative when compared with invasive ductal carcinoma. The authors report the case of a 72-year-old female patient, presenting with a breast lump, whose biopsy revealed a probable MBC with chondroid differentiation. She underwent a breast conservative surgery (BCS) and axillary sentinel lymph node dissection (SLND). The pathological report was concordant with the biopsy, and the patient was proposed to chemoradiotherapy. Despite its rarity and more severe features at diagnosis, BCS plus SLND plus radiotherapy should be offered to these patients, associated with chemotherapy. Chondroid differentiation is the rarest of all histological subtypes.