Primary myoepithelial carcinoma of palate

The aim of this study was to present a rare neoplasm, Primary myoepithelial carcinoma arising from the palate, and to review its diagnostic criteria, pathologic and clinical characteristics, treatment options and prognosis.

Myoepitheliomas are tumors arising from myoepithelial cells mainly or exclusively. Myoepitheliomas mostly occur in salivary glands, as well as in breast, skin, and lung. Case of myoepitheliomas in palate has rarely been reported. Myoepithelial carcinoma is malignant counterpart of myoepitheliomas. Adenomyoepithelioma is also a different disease from myoepitheliaomas. Immunohistochemically, tumor cells of myoepithelial carcinoma express not only epithelial markers such as cytokeratin, epithelial membrane antigen (EMA), but also markers of smooth muscle origin such as calponin. The immunohistochemical criteria of myoepithelial differentiation are double positive for both cytokeratins and one or more myoepithelial immunomarkers (i.e., S-100 protein, calponin, p63, GFAP, maspin, and actins). Myoepithelial carcinomas of salivary and breast demonstrate copy number gains and gene deletion. The overall prognosis of myoepithelial carcinoma is poor. There is rarely recurrence or metastasis in benign myoepithelial tumors. Complete excision with tumor-free margin is always the preferred treatment, while local radiation therapy and chemotherapy are suggestive treatment options. Here, a rare case of myoepithelial carcinoma arising from the palate has been described and discussed for the treatment and outcome. Pathological and clinical characters of myoepitheliomas are also compared and discussed.

The case report serves to increase awareness and improve the index of diagnosis and treatment of myoepitheliomas.