Salivary gland neoplasms account for approximately 3% of all head and neck tumors (1). Approximately 80% of salivary gland tumors are benign (6). The most common salivary gland tumor is benign pleomorphic adenoma (PA). Pleomorphic adenoma occurs in the 3rd to 5th decades, and favors women over men (6). Seventy five percent of pleomorphic adenomas occur in the superficial lobe of the parotid gland (2). The etiology of PA is unknown. However, there is a correlation between exposure to radiation, smoking, trauma, viruses, and genetic factors (6). The most common symptom of a PA is a slow growing painless mass (1,2,). FNA usually reveals a glistening, sticky substance (1).

FNA smears of pleomorphic adenoma exhibit a biphasic cell pattern with a background or interspersed chondroid matrix material. Cellularity is often moderate to marked with large, loose clusters of cells. Cells are found in clusters, cuboidal to polygonal in shape. Chromatin is fine and evenly distributed. Myoepithelial cells appear spindly, plasmacytoid, or stellate-shaped in the background. The background contains single plasmacytoid cells. Mesenchymal or chondromyxoid stroma most often appears feathery or fibrillary, without defined edges. With the Diff-Quik stain, the matrix stains a bright magenta color.

Other features of Pleomorphic Adenoma or mixed tumor of the salivary gland include tyrosine crystals, increased cellularity and mitotic activity, and an abundant myoepithelial component.