Performance de l´imagerie par résonance magnétique dans l´approche histopathologique des tumeurs parotidiennes

INTRODUCTION: salivary gland tumors mainly occur in the parotid gland. These tumors are rare but are characterized by histological heterogeneity, thus posing diagnostic challenges. Magnetic resonance imaging (MRI) is currently the most reliable imaging test for the evaluation of these tumors. The purpose of this study was to highlight the diagnostic value of MRI and its role in parotid gland tumor histopathology. METHODS: we conducted a retrospective descriptive and analytical study of 50 patients with parotid gland tumor, operated and treated in the ear, nose and throat (ENT) Department and in the Department of cervicofacial surgery at the Tahar Sfar University Hospital of Mahdia between 2001 and 2019. All patients underwent preoperative MRI of the parotid gland. RESULTS: out of 50 patients included in the study, 36 (72%) had benign tumor and 14 (28%) malignant tumor. The sensitivity of MRI for the diagnosis of malignant tumor was 92.8% with a specificity of 97.2%, a negative predictive value of 93% and a positive predictive value of 97%. With respect to benign tumor characterization, MRI suggested the diagnosis of Warthin tumor in all cases (13 cases) and of pleomorphic adenoma in 22 out of 23 cases. There were two diagnostic errors: MRI suggested the diagnosis of pleomorphic adenoma instead of adenoid cystic carcinoma in one case and of malignant tumor instead of pleomorphic adenoma due to diffusion restriction. CONCLUSION: MRI is highly efficient in the assessment of parotid tumor histology and, especially, after the advent of new functional sequences. However, only histological examination allows to confirm with certainty the diagnosis.