THE DEVELOPMENTAL stages of an internal neoplasm are rarely observed. When such a neoplasm occurs in a salivary gland tumor, it is possible by studying the histologic sequences to reach a better understanding of the interplay of hyperplasia, metaplasia, and neoplasia in an organ notable for its peculiar tumors.
In presenting two cases of salivary gland mucoepidermoid tumors, we also suggest that this term be limited to a well-defined group of relatively well-differentiated and rather benign tumors making up only part of the group designated as mucoepidermoid by Stewart, Foote, and Becker (1945).1 As thus limited, the term has a useful uniform clinicopathologic application in addition to being accurately descriptive. Reasons for excluding from this designation the much more malignant undifferentiated varieties are advanced. In particular, the differentiated mucoepidermoid salivary tumors are relatively slowly growing and radiosensitive, unlike many salivary gland cancers.
The cases to be reported, in which