Histomorphological comparison of pleomorphic adenoma in major and minor salivary glands of oral cavity: A comparative study

BACKGROUND AND OBJECTIVES: Pleomorphic adenoma, being the most common benign tumors of salivary gland, is morphologically characterized by a biphasic pattern containing the epithelial and mesenchymal components. The modified myoepithelial cells present are thought to play an important role in its histologic diversity by the formation of extracellular matrix. The aim of the present study was to observe, compare and correlate the histomorphological diversity of epithelial and stromal components along with different morphological cell types of modified myoepithelial cells. MATERIALS AND METHOD: Histomorphological features were compared in twenty cases of pleomorphic adenoma of major salivary glands and twenty cases of minor salivary glands using hematoxylin and eosin stains. The features were analyzed by observing under the light microscope. RESULTS: Statistical analysis showed significance of plasmacytoid cells, and squamous metaplasia was extensive with formation of keratin cyst-like structure resembling cystic pleomorphic adenoma, in minor salivary gland tumors. CONCLUSION: Plasmacytoid cells, squamous cells and areas of hyalinization were observed predominantly in major salivary gland tumors compared to minor salivary glands. Keratin pearls were predominant in minor salivary gland tumors.