The cell with a thousand faces: detection of myoepithelial cells and their contributions in the cytological diagnosis of salivary gland tumors

Myoepithelial cells are an important component of salivary gland tumors and are partly responsible from the diverse histology of them. In this study, we focus on the myoepithelial cell differentiation by using cytological morphology in a various types of salivary gland tumors especially with regard to their contribution to the diagnosis. The relation of myoepithelial cells with stromal matrix and the associated epithelial cells were evaluated. Cytologic slides of one hundred and forty one benign and twenty malignant salivary gland tumors were examined for identification of morphologically different myoepithelial cells such as; spindle-stellate, polygonal-epitheloid, plasmacytoid, basal and clear types. The best examples of myoepithelial cells were detected in pleomorphic adenomas, in some monomorphic adenomas and in the adenoid cystic carcinoma cases. Most of the pleomorphic adenomas were composed more than one type of myoepithelial cells and epitheloid-spindle cell combination was frequent. Basal and clear cell types of myoepithelial cells closely resembled the epithelial cells and their identification was relatively difficult. Identification of myoepithelial cell types was easier when they were associated with stromal matrix material and stood as a secondary layer around tubule-forming epithelial cells. Myoepithelial cell components of various salivary gland tumors may be quite different and identification of myoepithelial cell types may pose difficulties. A confident cytologic identification of myoepithelial cells may be critical part of diagnosing salivary gland tumors.