Differentiation and the cytomorphology of salivary gland tumors with specific reference to oncocytic metaplasia.

OBJECTIVE

The different cell types and many growth patterns found in salivary gland tumors provide ample reason for the diagnostic problems caused by these tumors. To improve criteria for differential diagnosis, the potential range of cytologic features possible in salivary gland tumor cells must be better appreciated.

STUDY DESIGN

From our respective pathology archives, normal salivary tissue and salivary gland tumours--other than Warthin's tumor and oncocytoma--with oncocytic differentiation were identified and studied by means of light and electron microscopy.

RESULTS

In this article, we cite a number of different salivary gland tumors, including basal cell adenoma, pleomorphic adenoma, myoepithelioma, polymorphous low-grade adenocarcinoma, and mucoepidermoid carcinoma, showing varying degrees of oncocytic differentiation.

CONCLUSIONS

Variable cellular differentiation is probably the basis for foci of tumor cells unexpected for a particular salivary gland neoplasm, further compounding differential diagnosis. Illustration of oncocytic differentiation serves 2 purposes. First, it can alert pathologists to this potential in otherwise typical salivary gland tumors; an awareness of this and other possible variations in cellular differential patterns can help prevent misdiagnosis. Second, these particular tumors illustrate the role of the cellular differentiation that is responsible for the range of histologic features within any one subtype of salivary gland tumors.