MALIGNANT MYOEPITHELIOMA OF BREAST: A RARE CASE REPORT AND REVIEW OF LITERATURE

Malignant myoepithelioma of the breast is an extremely rare neoplasm arising from myoepithelial cells that possess both epithelial and smooth muscle characteristics. This report presents the case of a 43 year old female with a painless, progressively enlarging lump in the right breast. Histopathological examination revealed malignant spindle and epithelioid cells in a chondromyxoid stroma with high nuclear cytoplasmic ratio and pleomorphism. Immunohistochemistry demonstrated strong positivity for S-100, Smooth muscle actin (SMA), calponin, vimentin, and p63, confirming myoepithelial origin, while estrogen receptor (ER), progesterone receptor (PR), and cytokeratin 5/6 were negative. The patient underwent modified radical mastectomy following neoadjuvant chemotherapy, with six metastatic lymph nodes identified. Literature review emphasizes the diagnostic challenge of distinguishing this entity from other spindle cell lesions of the breast. Early recognition through immunohistochemistry and a multidisciplinary therapeutic approach are crucial for management and improving patient prognosis.