JAPANESE JOURNAL OF ORAL & MAXILLOFACIAL SURGERY

Vol. 54 No. 6       2008

ISSN: 0021-5163      UBIC: 151-J

ABSTRACT

A case of epithelial-myoepithelial carcinoma transformed in pleomorphic adenoma occurring in palate of a 61 years old woman is reported. The tumor was composed of 2 different components, pleomorphic adenoma and epithelial myoepithelial carcinoma, accounting for approximately 40% and 60 % of whole tumor, respectively. As the results of the immunohistopathologic study, epithelial-myoepithelial carcinoma showed multiple tubular or solid nest, which were separated by a basement membrane and considered of variable proportion of 2 cell types, cuboidal epithelial cells positive for cytokeratin and clear myoepitlielial cells positive for glial fibrillary acid protein, wheres the myoepithelial nest of pleomorphic adenoma intermingled with hyaline and myxoid stroma. The malignancy was demonstrated by convincing evidence of invasion into the submucosa, although the epithelial-myoepithelial carcinoma component was mostly surrounded by the pleomorphic adenoma components. An increased immunoreactivity of proliferating cell nuclear antign in the epitlielial myoepithelial carcinoma area in comparison to the pleomorphic adenoma also suggested epithelial-myoepithelial carcinoma arising in a pleomorphic adenoma. Key words: epithelial-myoepithelial carcinoma, pleomorphic adenoma, immunohistopathologic study.

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