MALIGNANT MYOEPITHELIOMA OF THE BREAST - A CASE-HISTORY AND REVIEW OFLITERATURE

A malignant myoepithelioma, mainly intraductally growing, of the breas t was studied, emphasizing the immunohistological features of such tum ors, in comparison with the more common, architecturally similar, infi ltrating ductal carcinoma with intraductal component. Immunohistochemi cally, cell population of the tumor studied expressed intense reaction to alpha-SM-actin, cytokeratin 14, vimentin, S-100 protein and collag en IV antibodies, confirming myoepithelial differentiation. Since myoe pitheliomas of the breast are very rare, complete knowledge of these n eoplasms has not been attained. Nevertheless, histogenetic investigati ons may be useful in differentiating this type of tumor, from the abov e one, which is known to be characterized by severe clinical and progn ostic implications.