Diagnostic Value of Intraoperative Frozen Section in Parotid Gland Tumors: A Retrospective Study of 74 Cases

Objective: Parotid gland tumors present diagnostic and therapeutic challenges due to their wide histopathologic spectrum. This study aimed to evaluate the diagnostic accuracy of intraoperative frozen section (FS) examination in parotid tumors by comparing FS results with final histopathology, and to assess its utility in guiding surgical management.

Methods: We conducted a retrospective observational study of 74 patients who underwent parotidectomy with intraoperative FS at the Mohammed VI University Hospital in Marrakech between January 2018 and December 2023. FS diagnoses were compared with final histopathological results. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and error rates were calculated.

Results: Among 74 patients (mean age: 47 years), FS suggested a benign tumor in 52 cases (70.3%) and a malignant tumor in 22 cases (29.7%). Final histology confirmed 50 benign neoplasms (67.6%) and 24 malignant tumors (32.4%). FS showed a sensitivity of 90%, specificity of 89%, PPV of 80%, NPV of 96%, and an overall accuracy of 89%. Discrepancies occurred in 7 cases (9.5%), mainly due to misclassification of low-grade malignancies as benign neoplasms. The most common benign tumor was pleomorphic adenoma (59.4%) and the most frequent malignancy was mucoepidermoid carcinoma (12.1%).

Conclusion: Intraoperative frozen section is a reliable tool for distinguishing between benign and malignant parotid tumors. When integrated with clinical and radiological findings, FS can significantly improve intraoperative decision-making, allowing for appropriate surgical planning and minimizing the risks of over- or under-treatment.