RESUMEN
The aim of this descriptive study was to determine the frequency of pleomorphic adenoma of oral minor salivary glands according to sex, and age and different site of tumor, in patients referring to Mashhad Dental School. Among the total number of 8115 biopsies taken during years 1349 to1384 at oromaxillofacialpathology department of Mashhad Dental School, 120 cases of oral minor salivary glands tumors were detected and selected for the study. Two time intervals of A [1349-1375] and B [1375-1384] were considered in which the frequency of pleomorphic adenoma was compared according to age, sex and site of the lesion. The frequency of benign and malignant tumors of oral minor salivary gland tumors was also determined. Pleomorphic adenoma with the frequency percentage of 29.16 was the most benign tumor in oral minor salivary glands. The most frequent age of pleomorphic adenoma involvement was different between the two time intervals. The percentage of benign to malignant tumors was higher in the first interval. Pleomorphic adenoma was the most frequent oral minor salivary glands neoplasm especially in thepalate. The onset age of involvement had decreased but female/ male ratio increased. Malignancy was more frequent in Interval B compared to A