Relative Frequency of Primary Salivary Gland Tumors: Multicenter Study of 796 Cases from Riyadh, Saudi Arabia

Background and Objectives: Salivary gland tumors (SGTs) are diverse lesions with varying morphological and clinical characteristics. Limited data exist on the distribution of SGTs in Saudi Arabia. We aimed to fill this gap by examining the distribution of SGTs across four tertiary hospitals in Riyadh. Materials and Methods: A retrospective analysis was conducted on SGT cases diagnosed from January 2010 to December 2022 to investigate the clinicopathological features (tumor location, patient sex, and age). Histological slides were evaluated by two independent certified oral pathologists and classified based on the latest 2022 World Health Organization classification (WHO). Results: There were 796 SGTs. Most cases occur in individuals in their 4th to 5th decades of life. The parotid gland was the predominant site (79.4%), followed by the submandibular gland (9.3%). More than half of the tumors (527, 66.2%) were benign, involving major and minor salivary glands. Pleomorphic adenoma was the most common benign tumor, accounting for 354 cases (44.5%), followed by Warthin tumor with 117 cases (14.7%). Mucoepidermoid carcinoma was the most prevalent malignant tumor, identified in 98 patients (12.3%). Additionally, 36 (4.5%) mesenchymal and 30 (3.8%) hematolymphoid non-epithelial SGTs were reported. Conclusions: This multicenter study is the largest of its kind in Saudi Arabia, identifying pleomorphic adenoma and mucoepidermoid carcinoma as the most commonly reported benign and malignant tumors, respectively. These findings offer valuable insights into the understanding of salivary gland tumors globally.