HISTOLOGIC VARIANT OF THE EPITHELIAL-MYOEPITHELIAL CARCINOMA OF THE SALIVARY-GLAND - A CASE-REPORT

Background. Epithetlial-myoepithelial carcinoma (EMC) of the salivary gland is a low-grade carcinoma. It has been widely accepted as a clini copathologic entity only in the past decade. Histologically, the class ical bimodal differentiation of inner eosinophilic ductal cells and ou ter layer of clear myoepithelial cells has been well documented by man y authors. However, the proportion of each component may vary in diffe rent tumors or within the same tumor, and different histologic pattern s have been described. The clinicopathologic findings of an epithelial -myoepithelial carcinoma of the parotid gland in a 73-year-old man are presented. Methods. Light microscopy including immunohistochemistry a nd ultrastructural studies were done. Results. The various histologic patterns and bimodal differentiation of the tumor were noted. Conclusi ons. The present case demonstrates the myriad of histologic patterns t hat can occur in epithelial-myoepithelial carcinoma. Differentiation f rom malignant mixed tumor is essential and possible. The importance of the awareness of its histologic variants is emphasized. (C) 1995 John Wiley & Sons, Inc.