Myoepithelioma of the soft tissue of the head and neck: a case report and review of the literature.

Abstract

Extraglandular myoepitheliomas are neoplasms that seldom occur in the soft tissue of the head and neck region. Misdiagnosis of these neoplasms as more aggressive tumors can lead to unnecessary treatment. We describe a myoepithelioma of cervical soft tissue. The histopathology of the tumor, its immunophenotype, its differential diagnosis, and a review of the literature are presented. Histopathologically, the tumor was composed of epithelioid cells with eosinophilic cytoplasm and eccentric nuclei arranged in cords and files. On immunohistochemical analysis, the cells expressed cytokeratin 14, calponin, glial fibrillary acid protein, and p63 and showed focal positivity for S-100 protein. Together, these markers identified the cells as myoepithelial type. A literature review identified only five cases of myoepithelioma in the soft tissue of the head and neck region in which detailed clinical information was provided. Myoepitheliomas can have cells with variable morphology arranged in different histologic patterns. Immunohistochemical analysis is crucial for unequivocal diagnosis when myoepitheliomas occur in extraglandular locations.