We report a case of axillary metaplastic breast carcinoma (MBC) with triple negative (ER−/PR−/Her2−) phenotype, concurrent with multifocal invasive ductal carcinoma (IDC) of ipsilateral pectoral breast (ER+/PR+/Her2−) in a 60-year-old woman. Here, ESR1 is linked to invasive ductal breast carcinoma.