MALIGNANT MYOEPITHELIOMA OF THE MINOR SALIVARY-GLANDS ARISING IN A PLEOMORPHIC ADENOMA

This paper reports a case of carcinoma ex pleomorphic adenoma of the m inor salivary glands, where the carcinomatous component was a malignan t myoepithelioma (myoepithelial carcinoma). Immunohistochemical invest igation 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 for laminin and collagen IV around the neoplastic islands. These data are the confirmation that t he carcinoma cells were myoepithelial. The number of mitoses, the isto type, 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.