F M Cheung1, F Hioe, J H Kong. 1. Department of Pathology, Pamela Youde Nethersole Eastern Hospital, Chaiwan, Hong Kong.
Abstract
BACKGROUND: Epithelial-myoepithelial carcinoma (EMC) of the salivary gland is a low-grade carcinoma. It has been widely accepted as a clinicopathologic entity only in the past decade. Histologically, the classical bimodal differentiation of inner eosinophilic ductal cells and outer layer of clear myoepithelial cells has been well documented by many authors. However, the proportion of each component may vary in different tumors or within the same tumor, and different histologic patterns 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 and ultrastructural studies were done. RESULTS: The various histologic patterns and bimodal differentiation of the tumor were noted. CONCLUSIONS: The present case demonstrates the myriad of histologic patterns that can occur in epithelial-myoepithelial carcinoma. Differentiation from malignant mixed tumor is essential and possible. The importance of the awareness of its histologic variants is emphasized.
BACKGROUND:Epithelial-myoepithelial carcinoma (EMC) of the salivary gland is a low-grade carcinoma. It has been widely accepted as a clinicopathologic entity only in the past decade. Histologically, the classical bimodal differentiation of inner eosinophilic ductal cells and outer layer of clear myoepithelial cells has been well documented by many authors. However, the proportion of each component may vary in different tumors or within the same tumor, and different histologic patterns 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 and ultrastructural studies were done. RESULTS: The various histologic patterns and bimodal differentiation of the tumor were noted. CONCLUSIONS: The present case demonstrates the myriad of histologic patterns that can occur in epithelial-myoepithelial carcinoma. Differentiation from malignant mixed tumor is essential and possible. The importance of the awareness of its histologic variants is emphasized.