Metaplastic Carcinoma of the Breast, Spindle Cell Type: A Case Report

Metaplastic breast carcinoma accounts for less than 1% of all breast malignancies. This subtype is the most aggressive triple negative breast cancer and remains therapeutically challenging to treat, highly unresponsive to chemotherapy. Here we present a case of a 54 year old female presenting as a non-tender, left breast mass. Core needle biopsy reports atypical cells present, suggestive of malignancy: considerations are Malignant Phyllodes tumor and Invasive Ductal Carcinoma. Subsequently she underwent a modified radical mastectomy (MRM). Microscopic examination revealed spindle cell neoplasm without epithelial component. On immunohistochemically examination, the tumor cells were positive for Cytokeratin and Smooth Muscle Actin and negative for S-100, ER (Estrogen receptors), PR (progesterone receptors) and Her2/Neu.