Mucoepidermoid tumors of salivary glands

Abstract

A DISTINCTM group of neoplasms of the major and minor salivary glands, They arise from ducts and are composed of 2 main types of cellsmucin-containing cells and squamous cells-as well as other cells morphologically described as basal cells, intermediate cells, columnar cells, clear or hydropic cells, and oxyphilic cells.The frequency of occurrence of these cells varies in different tumors and in different areas within the same specimen.We will restrict the definition to include only tumors with welldeveloped squamous cell and mucinproducing cell components that are easily recognizable with hematoxylin and eosin stain.The reasons for this will become apparent in comparisons of the correlation between histological findings and natural history of the disease in our series with those of other authors.The first report of a series of these tumors with correlation of morphology and course of the disease was written by Stewart, Foote, and Becker in 1945.10They reported 45 mucoepidermoid tumors in 700 neoplasms of major and minor salivary glands seen in a 15-year period at Memorial Hospital for Cancer and Allied Diseases, New York, N.Y., an incidence of 6.4%.Thirtyone of the mucoepidermoid tumors were in major salivary glands; 21 were classified as benign and 10 malignant on the basis of their morphologic features and behavior.The authors cautioned that "benign" did not mean innocent and that it might be prelerable to speak of "relatively favorable" and "highly unfavorable" groups.The relatively favorable tumors had not metastasized.The majority of benign tumors measured 2 to 3 cm. in greatest dimension, were ovoid, cystic or partially cystic, well circumscribed, and unencapsulated.The cystic spaces contained clear, opalescent, or blood-stained mucoid material.Histologically benign tumors were composed of many