Deep Lobe Parotid Tumors: A Systematic Review and Meta-analysis

Comparing the Double-Echo Steady State with Water Excitation and Constructive Interference in Steady State Sequence Techniques for Identifying Extracranial Facial Nerve and Tumor Positions in Patients with Parotid Tumors

BACKGROUND AND PURPOSE

Reliable preoperative visualization of facial nerve morphology and understanding the spatial relationship between the facial nerve and tumors in the parotid gland can help clinicians perform safe and effective surgeries. Hence, this study aimed to compare the image quality of extracranial facial nerves obtained by using double-echo steady state with water excitation (DESS-WE) and CISS sequences and evaluate their diagnostic efficacy in the localization of parotid tumors.

MATERIALS AND METHODS

In total, 32 facial nerves of 16 healthy volunteers and 25 facial nerves of 25 patients with parotid tumors were included in this retrospective study. All participants underwent noncontrast-enhanced extracranial facial nerve MR imaging with DESS-WE and CISS with a 3T MR scanner equipped with a 64-channel head and neck coil. Image quality was subjectively evaluated by using a 5-point Likert scale by 2 radiologists. Inter- and intrarater agreements were assessed by using the Cohen κ coefficient. Receiver operating characteristic analysis was performed, and the diagnostic efficacies of DESS-WE and CISS images in localizing parotid tumors were calculated.

RESULTS

For healthy volunteers (11 men and 5 women; median age, 26 years), image quality scores for CISS were significantly higher than those for DESS-WE for the discrimination of the temporofacial and cervicofacial trunks (both, P < .001). In patients with parotid tumors (12 men and 13 women; median age, 58 years), CISS performed better than DESS-WE in terms of visualizing the spatial relationship of the facial nerve to the tumor and diagnostic confidence (both, P < .001). Regarding the localization of parotid tumors, CISS showed excellent performance, comparable to that of DESS-WE (area under the curve, 0.981 versus 0.942, P = .1489).

CONCLUSIONS

CISS achieved diagnostic performance comparable to DESS-WE in parotid tumor localization, with favorable image quality and more reliable morphologic visualization of the facial nerve.

Parotidectomy for deep lobe pleomorphic adenomas is associated with higher rates of complications and recurrence

BACKGROUND

Pleomorphic adenoma (PA) is a common parotid tumor, yet due to the relative rarity of deep lobe PA (DLPA), there is a paucity of information about its clinical presentation and surgical outcomes.

METHODS

We reviewed the charts of patients with previously untreated parotid PA between the years 1990 and 2015. Clinical parameters and surgical outcomes were compared between superficial lobe PA (SLPA) and DLPA.

RESULTS

The cohort comprised 147 cases of DLPA and 222 cases of SLPA. DLPA were larger (median 2.6 cm vs. 2.0 cm, p < 0.001), more often discovered incidentally on imaging (33%, n = 48) and had unique presentations (pharyngeal mass, dysphagia, otalgia). Postsurgical complications were more frequently observed in DLPA (41% vs. 30% in SLPA, p = 0.025), mainly transient facial nerve weakness. DLPA also showed higher recurrence rates (n = 6, 4.1% vs. n = 1, 0.4%, p = 0.016).

CONCLUSIONS

Parotidectomy for DLPA carries a higher risk of complications and recurrence compared to SLPA.

Algorithm for the reconstruction of the parotid region: a single institution experience

OBJECTIVE

This study aims to discuss the characteristics and treatment methods of malignant tumors in the parotid region, as well as the therapeutic effects of immediate free flap reconstruction of soft tissue for postoperative defects.

MATERIALS AND METHODS

A retrospective review was conducted on 11 cases of soft tissue flap reconstruction for postoperative defects following the resection of malignant tumors in the parotid region. Statistical analysis was performed based on clinical data.

RESULTS

Among the 11 cases of malignant tumors in the parotid region, there were 2 cases of secretory carcinoma (SC) of the salivary gland, 2 cases of squamous cell carcinoma (SCC), 2 cases of carcinosarcoma, 1 case of mucoepidermoid carcinoma (MEC), 1 case of epithelial-myoepithelial carcinoma (EMC), 1 case of salivary duct carcinoma (SDC), 1 case of basal cell carcinoma (BCC), and 1 case of osteosarcoma. Among these cases, 4 were initial diagnoses and 7 were recurrent tumors. The defect repairs involved: 8 cases with anterolateral thigh free flap (ALTF), 2 cases with pectoralis major muscle flaps, and 1 case with forearm flap. The size of the flaps ranged from approximately 1 cm × 3 cm to 7 cm × 15 cm. The recipient vessels included: 4 cases with the facial artery, 4 cases with the superior thyroid artery, and 1 case with the external carotid artery. The ratio of recipient vein anastomosis was: 57% for branches of the internal jugular vein, 29% for the facial vein, and 14% for the external jugular vein. Among the 8 cases that underwent neck lymph node dissection, one case showed lymph node metastasis on pathological examination. In the initial diagnosis cases, 2 cases received postoperative radiotherapy, and 1 case received 125I seed implantation therapeutic treatment after experiencing two recurrences. Postoperative follow-up revealed that 2 cases underwent reoperation due to local tumor recurrence, and there were 2 cases lost to follow-up. The survival outcomes after treatment included: one case of distant metastasis and one case of death from non-cancerous diseases.

CONCLUSION

Immediate soft tissue flap reconstruction is an important and valuable option to address postoperative defects in patients afflicted with malignant tumors in the parotid region.

Application of ultrasound in distinguishing the incipient microtumor from inherent lymph nodes of the parotid glands

BACKGROUND

Parotid microtumors (size ≤ 1 cm) pose a significant clinical challenge due to their malignant potential and risks associated with surgery. It is imperative to explore the diagnostic workflow that incorporates ultrasound (US) in order to make appropriate clinical decisions with minimal invasiveness.

METHODS

The patients receiving both US and ultrasound-guided fine needle aspiration (USFNA) for the parotid microtumors in a medical center were retrospectively recruited. The ultrasonic features, cytology of USFNA, and final surgical pathology were analyzed to differentiate the tumor origins and their malignant potential.

RESULTS

From August 2009 to March 2016, a total of 92 patients were enrolled in the study. The short axis, long-to-short axis ratio, and presence of an echogenic hilum were found to be significantly useful in distinguishing lymphoid tissue origin from salivary gland origin, which was confirmed by USFNA. An irregular border was predictive for malignant parotid microtumors from both origins. Intra-tumoral heterogeneity was also identified as a significant feature associated with malignant lymph nodes. USFNA was able to confirm all malignant lymph nodes, but it had a false negative rate of 8.5% in parotid microtumors of salivary gland origin. Based on the analysis of US and USFNA results, a diagnostic workflow for parotid microtumors was proposed.

CONCLUSION

US and USFNA can be helpful in classifying the origins of parotid microtumors. US-FNA carries the risk of producing false negative results specifically for microtumors originating from salivary glands, but not lymphoid tissue. The diagnostic workflow, which incorporates both US and USFNA, assists in determining the clinical decision for diagnosing and managing parotid microtumors.

Is the combined use of ultrasonography (USG) and fine needle aspiration biopsy (FNAB) safe in parotis masses? Retrospective comprehensive comparison of 123 cases

OBJECTIVES

The purpose of the study was to compare final pathology results with ultrasonography (USI) and fine needle aspiration biopsy (FNAB) results in parotis masses.

METHODS

A total of 123 patients with primary parotis mass who applied to our center between 2010 and 2020 were selected for the study. Among these, 100 patients with preoperative USI, preoperative FNAB, and postoperative final pathology were included in the study. USI, FNAB, pathology results, surgery types, and demographic characteristics of the patients were analyzed.

RESULTS

According to the postoperative final pathology, preoperative USI sensitivity was found to be 100%, specificity was 55, positive predictive value was 84.31%, negative predictive value was 100%, and accuracy was 86.89%. Preoperative FNAB had a sensitivity of 85.7%, a specificity of 92.1%, a positive predictive value of 82.1%, a negative predictive value of 90.2%, and a diagnostic accuracy of 89.3%, according to the postoperative final pathology.

CONCLUSION

Preoperative USI and preoperative FNAB are very valuable diagnostic tools in the evaluation of parotis lesions. When used together, they provide highly accurate and important data for the surgeon.

Extracapsular Dissection of Deep Lobe Parotid Mass Aided by Retromandibular Vein on Imaging: A Case Report

This report investigates the use of the retromandibular vein on imaging as a diagnostic tool for planning deep lobe parotid tumors. A unique aspect of this case is the performance of extracapsular dissection on a deep lobe parotid lesion, which is rare. Preoperative imaging showed a superficially displaced retromandibular vein, indicating a deeply seated tumor, which aided surgical planning. Under general anesthesia, extracapsular dissection was performed while protecting the facial nerve branches. The patient's postoperative course was uneventful, and the facial nerve was intact with no weakness.

Proposal for a novel classification of benign parotid tumors based on localization

OBJECTIVE

Postoperative facial nerve paralysis is the most problematic complication after surgical treatment of parotid tumors. Localization of tumors is highly relevant for the surgical approach, but existing classification systems do not focus on the association between localization and surgical technique. Therefore, we created a new localization-based classification system for benign parotid tumors and investigated the characteristics of tumors in each localization and the frequency of postoperative facial nerve paralysis by retrospectively applying the classification to previous cases.

METHODS

First, we defined 6 portions of the parotid gland (upper, U; lower, L; posterior, P; anterior, A; superficial, S; deep, D) by dividing the transverse plane into an upper and lower portion at the mandibular marginal branch, the longitudinal plane into a posterior and anterior portion at the midline of the parotid anteroposterior diameter, and the sagittal plane into a superficial and deep portion along the course of the facial nerve. Then, we defined 8 locations by combining the 6 portions in all possible ways (i.e., U-P-S, U-P-D, U-A-S, U-A-D, L-P-S, L-P-D, L-A-S, L-A-D). We used this classification to define the tumor localization in 948 patients who had undergone partial superficial parotidectomy for benign parotid tumors and then investigated the incidence, histopathological type, signs/symptoms, diagnosis, surgery, and complications in each area.

RESULTS

Pleomorphic adenomas comprised approximately 70% of tumors in the upper portion but only approximately 35% in the lower portion. The rate of postoperative facial nerve paralysis was significantly higher for tumors in deep locations than in superficial locations (33.9% vs 14.9%, respectively), and the odds ratios for postoperative facial nerve paralysis in the U-P-D and U-A-D locations were 7.6 and 4.8 compared to the L-P-S location. When maximum diameter, operation time, bleeding volume, sex (reference: female), and age were added as control variables, the odds ratios were 4.2 and 3.0.

CONCLUSION

Determining tumor localization preoperatively with the new localization-based classification of parotid tumors is helpful not only for predicting the histopathological type but also for predicting surgical complications, particularly postoperative facial nerve paralysis.

Multiphasic CT-Based Radiomics Analysis for the Differentiation of Benign and Malignant Parotid Tumors

Objective

This study aims to investigate the value of machine learning models based on clinical-radiological features and multiphasic CT radiomics features in the differentiation of benign parotid tumors (BPTs) and malignant parotid tumors (MPTs).

Methods

This retrospective study included 312 patients (205 cases of BPTs and 107 cases of MPTs) who underwent multiphasic enhanced CT examinations, which were randomly divided into training (N = 218) and test (N = 94) sets. The radiomics features were extracted from the plain, arterial, and venous phases. The synthetic minority oversampling technique was used to balance minority class samples in the training set. Feature selection methods were done using the least absolute shrinkage and selection operator (LASSO), mutual information (MI), and recursive feature extraction (RFE). Two machine learning classifiers, support vector machine (SVM), and logistic regression (LR), were then combined in pairs with three feature selection methods to build different radiomics models. Meanwhile, the prediction performances of different radiomics models based on single phase (plain, arterial, and venous phase) and multiphase (three-phase combination) were compared to determine which model construction method and phase were more discriminative. In addition, clinical models based on clinical-radiological features and combined models integrating radiomics features and clinical-radiological features were established. The prediction performances of the different models were evaluated by the area under the receiver operating characteristic (ROC) curve (AUC) and the drawing of calibration curves.

Results

Among the 24 established radiomics models composed of four different phases, three feature selection methods, and two machine learning classifiers, the LASSO-SVM model based on a three-phase combination had the optimal prediction performance with AUC (0.936 [95% CI = 0.866, 0.976]), sensitivity (0.78), specificity (0.90), and accuracy (0.86) in the test set, and its prediction performance was significantly better than with the clinical model based on LR (AUC = 0.781, p = 0.012). In the test set, the combined model based on LR had a lower AUC than the optimal radiomics model (AUC = 0.933 vs. 0.936), but no statistically significant difference (p = 0.888).

Conclusion

Multiphasic CT-based radiomics analysis showed a machine learning model based on clinical-radiological features and radiomics features has the potential to provide a valuable tool for discriminating benign from malignant parotid tumors.

Surgical management of deep lobe parotid tumours with and without involvement of the parapharyngeal space

The diagnosis and treatment of deep lobe parotid tumours is challenging because of the complex surgical accessibility. There is a lack of studies describing the differences between deep lobe tumours that do and do not occupy the parapharyngeal space (PPS). Patients treated for deep lobe tumours occupying the PPS (PPS group) and not occupying the PPS (non-PPS group) were analysed retrospectively. A total of 227 patients were treated surgically for deep lobe parotid tumours between 1990 and 2019. Sixty patients (26.4%) presented with tumours that involved the PPS (PPS group), while 167 (73.6%) presented with tumours that did not occupy the PPS (non-PPS group). The majority of the PPS group tumours were removed using a transcervical or transcervical-transparotid approach. PPS group tumours were larger (P < 0.001), and tumour spill occurred more frequently in this group (benign tumours: P = 0.002; malignant tumours: P = 0.033). Complication rates did not differ between the PPS and non-PPS groups. A transcervical or transcervical-transparotid approach is the preferred method for the management of deep lobe parotid tumours that occupy the PPS in our practice. Tumour spill occurred more frequently in the PPS group, which is most probably due to the larger tumour size and more complex accessibility.

Selective deep lobe parotidectomy via retroauricular hairline (Roh's) incision for deep lobe parotid pleomorphic adenoma

OBJECTIVE

Deep lobe parotid tumour is commonly removed with the covering superficial lobe of parotid gland. Total or subtotal parotidectomy leads to an increase in surgical morbidity. This study evaluated recurrence and function after selective deep lobe parotidectomy via retroauricular hairline (Roh's) incision for pleomorphic adenoma.

MATERIALS AND METHODS

Twenty-eight patients with deep lobe parotid pleomorphic adenomas underwent selective deep lobe parotidectomy with preservation of the superficial lobe and the facial lobe via Roh's incision. Each patient was evaluated with any complications, cosmetic and salivary functions and local recurrence.

RESULTS

Superficial lobe-preserving surgery via Roh's incision was successfully applied to all patients without injury to the facial nerve and the Stensen's duct for a median operation time of 65 min. Facial nerve paralysis was found only temporarily in 9 (32%) patients, and other complications were minimal. None of the patients had postoperative Frey's syndrome. Salivary secretory function in the operated side was well preserved. No recurrence was found in the patients for a median follow-up of 94 months.

CONCLUSIONS

Selective deep lobe parotidectomy via Roh's incision is a reliable option of treatment for deep lobe parotid pleomorphic adenoma.