Oral cavity salivary gland pleomorphic adenoma: a histomorphological case series

Background: Pleomorphic adenoma (PA), the most common benign salivary gland epithelial lesion, has a biphasic epithelial-mesenchymal pattern and great histopathological diversity. Methods: This study's objective was to conduct a retrospective clinicopathological analysis, focusing on the histopathology characteristics of salivary gland PA. Results: There were ten cases of pleomorphic adenoma. The mean age was 33.5 years and no gender predilection was observed. All the patients presented with an asymptomatic mass and the duration of presentation was 31.2 +/- 19.4 months. The cellular subtype (50 %) of PA was the most common. Capsular infiltration and incomplete capsules occurred in 20 % of cases. All the cases had round (100 %) and myxoid stroma. The cellular subtype was more common in the major salivary glands; showed capsular abnormalities (incomplete capsule, absent capsule, and tumor infiltration); and had more plasmacytoid, angular, spindled non-luminal cells as well as inflammation and cystic degeneration. The classic subtype had more clear and oncocytic cells along with sebaceous and squamous differentiation. The stroma-rich subtype had the shortest duration of complaints (three months) and showed giant cell reaction. Conclusions: These findings confirm previous studies on the clinicopathological features of pleomorphic adenomas and highlight important morphologic characteristics like capsular invasion and squamous metaplasia, which can otherwise indicate malignancy.