Most of malignant tumors of the larynx are squamous cell carcinomas, and there are only a very few cases of other malignant tumors in this organ. We encountered a very rare malignant pleomorphic adenoma occurring in the larynx. It is histologically understood that this tumor is formed as a result of atypical neoplastic growth of both epithelial and mesenchymal cells.
An immunohistological study was also made on this case, in which immunohistological reactions to keratin (an intermediate filament of epithelial cell), the epithelial membrane antigen (EMA) and vimentin (an intermediate filament of mesenchymal cell) were examined. As a result, positive reactions were obtained for both keratin and EMA along with tumor cells showing alveolar growth or canalicular structure, while vimentine-positive findings were congruous with roundish and spindle cells indicating cartilagenous formation.
Our immunohistological findings clearly revealed the distribution of tumor components showing the differentiation into epithelial cells as well as into mesenchymal cells. Since the tumor was relatively localized in the epiglottis with apparent expansion into the vallecula, horizontal partial laryngectomy in combination with preand postoperative irradiation was performed with a successful result.
