Malignant myoepithelioma of the minor salivary glands arising in a pleomorphic adenoma.

This paper reports a case of carcinoma expleomorphic adenoma of the minor salivary glands, where the carcinomatous component was a malignant myoepithelioma (myoepithelial carcinoma). Immunohistochemical investigation showed that the carcinoma cells were positive for cytokeratin, S-100 protein and vimentin, and focally positive for actin and desmin. A moderate level of positivity was found fo laminin and collagen IV around the neoplastic islands. These data are the confirmation that the carcinoma cells were myoepithelial. The number of mitoses, the istotype, the minimal extent of extracapsular infiltration and the absence of vascular invasion made it possible to include this particular case among those with a better prognosis.