Diagnostic Contribution of Magnetic Resonance Imaging in Pleomorphic Adenoma of the Parotid Gland: A Six-Year Experience at Avicenne Military Hospital, Marrakech

Objective: This study aimed to assess the diagnostic accuracy and overall contribution of magnetic resonance imaging (MRI) in the preoperative characterization of pleomorphic adenoma (PA) of the parotid gland in a Moroccan tertiary military medical center.

Patients and Methods: A retrospective longitudinal study was conducted over six years (2015–2020), including patients who presented with a parotid mass, underwent MRI of the parotid region, subsequently underwent surgical excision, and were finally diagnosed with pleomorphic adenoma on histopathology.

Results: Thirty patients met the inclusion criteria. The mean age was 36.6 years (range: 14–72), with a slight female predominance (53.3%). The mean duration before consultation was 4 years. MRI localized the tumor to the superficial lobe in 76.7% of cases, the deep lobe in 13.3%, and both lobes in 10%. The mean MRI-measured tumor size was 30 mm. Superficial parotidectomy was performed in 76.7% of patients. MRI suggested pleomorphic adenoma in all 30 patients; histopathology confirmed the diagnosis in 83.3%. Discordant findings included four Warthin tumors (13.3%) and one oncocytoma (3.3%). Typical MRI features—T1 hyposignal, T2 hypersignal, lobulated margins, and strong post-contrast enhancement—showed variable sensitivity and specificity.

Conclusion: In our six-year experience, MRI demonstrated a high diagnostic yield in identifying pleomorphic adenoma of the parotid gland. However, atypical imaging presentations and overlap with other benign lesions, particularly Warthin tumors, account for false-positive cases. Combining conventional MRI sequences with functional imaging modalities improves diagnostic accuracy and helps guide surgical planning.