Malignant myoepithelioma of the breast. Case report with immunohistochemical study

Malignant myoepitheliomas of the breast are rare. We report a case of spindle cell malignant myoepithelioma studied by light microscopy and immunohistochemistry. The malignant myoepithelial cells stained positively for cytokeratins, smooth muscle actin and vimentin, but not for epithelial membrane antigen. The tumor showed a focal positivity for S100 protein. A short review of the morphology and immunohistochemistry of cases reported in the international literature is given in a table. Morphologically malignant myoepitheliomas can be subdivided into spindle cell malignant myoepitheliomas and malignant adenomyoepitheliomas.