THE IMPORTANCE OF MR MONITORING AFTER SURGICAL TREATMENT OF PAROTID GLAND TUMORS
Bubnova E.V., Lukina O.V.
I.P. Pavlov First Saint Petersburg State Medical University. Saint Petersburg, Russia.
Purpose. To evaluate the value of magnetic resonance imaging in postoperative monitoring of patients with parotid gland neoplasms.
Materials and methods. The study included 87 patients who underwent surgery for primary or recurrent parotid salivary gland tumors at the Maxillofacial Surgery Clinic of the First Pavlov State Medical University of Saint Petersburg between June 13, 2013, and May 21, 2026 (a 13-year follow-up period).
Two groups were identified among the patients included in the study:
Group 1 (n=47) included patients who underwent both preoperative and follow-up postoperative magnetic resonance imaging of the soft tissues of the neck, with a focused examination of the parotid regions and contrast enhancement using a Signa HDxt (General Electric) 1.5 Tesla device at the Radiological Computed Tomography Departments of the Research and Clinical Center of Radiological Diagnostics and Radiotherapy at First Pavlov State Medical University of Saint Petersburg;
Group 2 (n=40) – patients with suspected recurrence of a neoplastic process at the time of soft tissue magnetic resonance imaging of the neck with focused examination of the parotid regions and contrast enhancement, who had previously undergone surgery for parotid salivary gland neoplasms but had not undergone high-tech radiological diagnostics (magnetic resonance imaging or computed tomography) before the primary surgical intervention.
Results. All patients in Group 1 (n=47) were operated on after performing magnetic resonance imaging, and the identified neoplasms were histologically verified. In most patients (39 patients (82.98%) out of 47 patients), the presence of benign neoplasms of the parotid salivary glands was histologically confirmed.
In patients who underwent surgery for both benign (n=39) and malignant (n=8) neoplasms, postoperative magnetic resonance imaging revealed asymmetry of the parotid regions of varying severity, a decrease in the volume of the operated parotid salivary gland, a decrease in the volume of the subcutaneous fat tissue of the parotid region, and fibrous scarring and traction changes in the surgical area. It should be noted that the severity of postoperative fibrotic scarring and traction changes varied from mild to severe, taking into account the size and location of the neoplasms in the parotid salivary gland structure at the preoperative stage.
A separate group was formed of patients with suspected recurrence of the neoplastic process (n=40), who did not undergo high-tech radiological diagnostics (magnetic resonance imaging and/or computed tomography) before the primary surgical intervention. During the examination before the repeated surgical intervention, all patients of this group underwent magnetic resonance imaging of soft tissues of the neck, during which the radiologist in all cases suggested the recurrence of the neoplastic process. In addition to postoperative fibrotic changes as a result of the initial surgical intervention, 29 patients (72.5%) out of 40 patients were found to have changes that were interpreted by the radiologist as a recurrence of pleomorphic adenoma - the "mercury droplets" symptom. All of the identified changes were confirmed histologically after the second surgical intervention.
Discussion. The formation of an adequate spatial vision of the neoplasm by the operating maxillofacial surgeon is impossible without a thorough anatomical assessment of the surgical intervention area, which is implemented by performing modern high-tech methods of radiological diagnostics. Understanding the anatomical features of the parotid salivary gland, the variants of the spread of the neoplastic process, as well as the relationship of the neoplasm with the facial nerve and vascular structures, is critical both in the planning of surgical intervention and in the prevention of recurrence of the neoplasm.
The value of adequate preoperative radiological imaging is shown in the analysis of the risk ratio of salivary gland neoplasms recurrence. The presence of recurrence has a significantly greater probability (shown odds ratio (OR) = 5.54 [95% confidence interval (CI):1.53;10.57], p<0.001)) in the group of patients who did not perform magnetic resonance imaging in the preoperative period. Insufficiency of only objective examination of the patient, even in combination with ultrasound examination, leads to an increase in the risk of recurrence.
The results of our study also show the importance of the localization of neoplasms in the formation of postoperative deformities.
When conducting a statistical analysis to assess the risks of postoperative changes, it was noted that there was a significant increase in the risk of deformation of the parotid regions in patients with tumors originating from or spreading to the pharyngeal process of the parotid salivary gland (odds ratio (OR) = 3.69 [95% confidence interval (CI): 2.53; 9.57], p<0.001). Therefore, this localization is an unfavorable factor when planning surgical treatment.
Conclusion. Magnetic resonance imaging should be included as a mandatory component in the examination algorithm for patients with suspected neoplastic processes in the parotid salivary glands, as an adequate anatomical assessment is a factor that determines both treatment tactics and the likelihood of recurrence.
Postoperative changes in patients with small tumors located in the superficial lobe of the parotid gland are characterized by less pronounced scarring and traction changes. At the same time, postoperative changes in patients with tumors originating from or spreading to the pharyngeal process of the parotid gland are pronounced and often require rehabilitation measures or plastic surgical interventions. Therefore, the parapharyngeal localization of parotid gland tumors is an unfavorable risk factor for the development of postoperative deformities.
A recurrence of a mixed tumor (pleomorphic adenoma) of the parotid salivary gland is characterized by a specific magnetic resonance symptom in the form of multiple rounded lesions located predominantly in the area of the initial surgical intervention, in the parapharyngeal space, or along the course of the postoperative fibrous scar, which have a hyperintense signal on T2-weighted images, a hypointense signal on T1-weighted images, and accumulate paramagnetic contrast agents after intravenous administration - the "mercury droplet symptom".
Keywords: magnetic resonance imaging, postoperative changes in the parotid region, recurrence of salivary gland tumors.
Corresponding author: Bubnova E.V., e-mail: Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript
For citation: Bubnova E.V., Lukina O.V. The importance of MR monitoring after surgical treatment of parotid gland tumors. REJR 2026; 16(2):32-45. DOI: 10.21569/2222-7415-2026-16-2-32-45.
Received: 25.03.26 Accepted: 01.08.26