Abstract

ABSTRACT Metaplastic breast cancer is a rare subtype of breast cancer that is histologically heterogeneous, being composed of both sarcomatous and epithelial components. It presents as rapidly growing palpable masses. Incidence of nodal metastasis is low, as compared to intraductal carcinoma, but it has a high metastatic potential and more chances of local recurrence. Many different pathological classifications are available, the most popular being "Wargotz and Norris classification". Imaging features mimic those of intraductal carcinoma. Immunohistochemically, these tumors show a basal/myoepithelial phenotype with positivity for cytokeratins, AE1/AE3, smooth muscle actin, p63, alpha B-crystallin, etc. These tumors show no or very low positivity for hormone receptors or HER-2 over expression. Therefore, they are often called triple negative carcinomas. They are aggressive tumors with suboptimal response to standard chemotherapy regimens. Overall prognosis of the patients with metaplastic breast cancer is worse than the patients with intraductal breast carcinoma. Further research is needed for formulating targeted therapies for this aggressive tumor.