Mixed metaplastic carcinoma of the breast: a case report.

A 68 year-old woman with no significant medical history discovered a lump incidentally in her left breast. The patient's initial imaging revealed a 4.6-cm irregular mass at 11:00 categorized as a BI-RADS 5 as well as an enlarged axillary lymph node and an area of 2.5 cm of heterogeneous calcifications in the 3 o'clock position. The 4.6-cm lesion was revealed to be infiltrating ductal carcinoma with a squamous component, mixed metaplastic carcinoma, which was strongly ER (100+)/PR (100+) positive, HER-2/Neu negative on FISH. The 2.5-cm calcifications were ductal carcinoma in situ. The patient completed neoadjuvant chemotherapy, and had an excellent response. After further discussion, the patient elected for breast conservation therapy and underwent a left wireless localized partial mastectomy with a left axillary dissection. Surgical pathology revealed a near complete pathologic response with only 8-mm residual tumour as well as a negative conversion of the clipped axillary node.