Deep learning-assisted diagnosis of benign and malignant parotid tumors based on ultrasound: a retrospective study

BACKGROUND

To develop a deep learning(DL) model utilizing ultrasound images, and evaluate its efficacy in distinguishing between benign and malignant parotid tumors (PTs), as well as its practicality in assisting clinicians with accurate diagnosis.

METHODS

A total of 2211 ultrasound images of 980 pathologically confirmed PTs (Training set: n = 721; Validation set: n = 82; Internal-test set: n = 89; External-test set: n = 88) from 907 patients were retrospectively included in this study. The optimal model was selected and the diagnostic performance evaluation is conducted by utilizing the area under curve (AUC) of the receiver-operating characteristic(ROC) based on five different DL networks constructed at varying depths. Furthermore, a comparison of different seniority radiologists was made in the presence of the optimal auxiliary diagnosis model. Additionally, the diagnostic confusion matrix of the optimal model was calculated, and an analysis and summary of misjudged cases' characteristics were conducted.

RESULTS

The Resnet18 demonstrated superior diagnostic performance, with an AUC value of 0.947, accuracy of 88.5%, sensitivity of 78.2%, and specificity of 92.7% in internal-test set, and with an AUC value of 0.925, accuracy of 89.8%, sensitivity of 83.3%, and specificity of 90.6% in external-test set. The PTs were subjectively assessed twice by six radiologists, both with and without the assisted of the model. With the assisted of the model, both junior and senior radiologists demonstrated enhanced diagnostic performance. In the internal-test set, there was an increase in AUC values by 0.062 and 0.082 for junior radiologists respectively, while senior radiologists experienced an improvement of 0.066 and 0.106 in their respective AUC values.

CONCLUSIONS

The DL model based on ultrasound images demonstrates exceptional capability in distinguishing between benign and malignant PTs, thereby assisting radiologists of varying expertise levels to achieve heightened diagnostic performance, and serve as a noninvasive imaging adjunct diagnostic method for clinical purposes.

Direct visualization of intraparotid facial nerve assisting in parotid tumor resection

Precise recognition of the intraparotid facial nerve (IFN) is crucial during parotid tumor resection. We aimed to explore the application effect of direct visualization of the IFN in parotid tumor resection. Fifteen patients with parotid tumors were enrolled in this study and underwent specific radiological scanning in which the IFNs were displayed as high-intensity images. After image segmentation, IFN could be preoperatively directly visualized. Mixed reality combined with surgical navigation were applied to intraoperatively directly visualize the segmentation results as real-time three-dimensional holograms, guiding the surgeons in IFN dissection and tumor resection. Radiological visibility of the IFN, accuracy of image segmentation and postoperative facial nerve function were analyzed. The trunks of IFN were directly visible in radiological images for all patients. Of 37 landmark points on the IFN, 36 were accurately segmented. Four patients were classified as House-Brackmann Grade I postoperatively. Two patients with malignancies had postoperative long-standing facial paralysis. Direct visualization of IFN was a feasible novel method with high accuracy that could assist in recognition of IFN and therefore potentially improve the treatment outcome of parotid tumor resection.

Tumor localization is the important factor for recovery time of postoperative facial nerve paralysis in benign parotid surgery

OBJECTIVE

Facial nerve paralysis is the most problematic complication of surgery for parotid tumors. This study aimed to examine the progress of recovery from postoperative transient facial nerve paralysis (POFNP).

METHODS

Participants were 203 patients who developed POFNP after benign parotid surgery. A Kaplan-Meier showed the progress of recovery from paralysis. Factors involved in recovery were examined. For factors for which a significant difference was found, recovery from paralysis was examined over time.

RESULTS

Rates of recovery from paralysis were as follows: 28.6% of patients at 1 month, 58.3% at 3 months, 85.9% at 6 months, and 95.1% at 12 months after surgery. Deep lobe tumors were shown to be significantly associated with delayed recovery from paralysis. The relationship between tumor location and the time of recovery from was that deep lobe tumors had a significantly worse recovery from paralysis at 4 and 5 months after surgery.

CONCLUSION

Patients who develop POFNP must be informed about the progress of recovery and factors involved in recovery from paralysis. We believe that the results of the present study are a useful reference to that end.

Epstein-Barr Virus-Associated Lymphoepithelial Carcinoma Arising in a Salivary Sebaceous Lymphadenoma

BACKGROUND

Lymphadenomas are rare benign tumors of the major salivary glands that are further classified as sebaceous and non-sebaceous. No association with viruses has been reported so far. Little is known about the mechanisms that allow lymphadenomas to undergo malignant transformation. Among these rare instances, there has never been a malignant transformation to Epstein-Barr virus (EBV)-associated lymphoepithelial carcinoma.

METHODS

Clinical data of the reported case were retrieved from the patient's electronic medical record. Hematoxylin & eosin-stained slides, immunohistochemical tests, and in situ hybridization performed for routine diagnostic purposes were reviewed.

RESULTS

We report a salivary gland sebaceous lymphadenoma in which the luminal components were mostly replaced by malignant epithelial cells with markedly atypical nuclear features. Presence of EBV was demonstrated in all components by EBER. The morphological and immunohistochemical findings were consistent with a lymphoepithelial carcinoma arising from a sebaceous lymphadenoma.

CONCLUSION

We report the first case of an Epstein-Barr virus-associated lymphoepithelial carcinoma arising from a sebaceous lymphadenoma.

Rare Presentation of Tuberculous Osteomyelitis of Mandibular Condyle Mimicking as Parotid Tumor: A Case Report

Tuberculosis (TB) is a significant health problem and mortality in most developing countries. It is a chronic granulomatous disease caused by Mycobacterium tuberculosis and M. tuberculosis complex. It can be pulmonary form or Extra pulmonary form. Extrapulmonary tuberculosis involving temporomandibular joint is infrequent presentation of Skeletal TB. Here we present a rare case of extrapulmonary tuberculosis that was initially misdiagnosed as a parotid lesion due to atypical signs and symptoms and multiple in-conclusive FNAC reports. The final diagnosis was established by histopathological report.

Common Tumor in an uncommon location: Pleomorphic Adenoma of nasal cavity - a case Report

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor of which parotid gland involvement is the most common. PA may arise from minor salivary glands as well, however, PA is very rare in the sinonasal and nasopharyngeal areas. It usually affects middle aged females. They are frequently misdiagnosed due to high cellularity and myxoid stroma, leading to delay in diagnosis & further appropriate management. Here we present a case report of a female who presented with gradually progressive nasal obstruction, on examination found to have a nasal mass in right nasal cavity. Imaging was done and the nasal mass was excised. Histopathological report revealed a PA. Common tumor in an uncommon location: Pleomorphic adenoma of the nasal cavity - a case report.

Current status of diffusion-weighted imaging in differentiating parotid tumors

Recently, diffusion-weighted imaging (DWI) is an essential magnetic resonance imaging (MRI) protocol for head and neck imaging in clinical practice as it plays an important role in lesion detection, tumor extension evaluation, differential diagnosis, therapeutic effect prediction, therapy evaluation, and recurrence diagnosis. Especially in the parotid gland, several studies have already attempted to achieve accurate differentiation between benign and malignant tumors using DWI. A conventional single-shot echo-planar-based DWI is widely used for head and neck imaging, whereas advanced DWI sequences, such as intravoxel incoherent motion, diffusion kurtosis imaging, periodically rotated overlapping parallel lines with enhanced reconstruction, and readout-segmented echo-planar imaging (readout segmentation of long variable echo-trains), have been used to characterize parotid tumors. The mean apparent diffusion coefficient values are easily measured and useful for assessing cellularity and histological characteristics, whereas advanced image analyses, such as histogram analysis, texture analysis, and machine and deep learning, have been rapidly developed. Furthermore, a combination of DWI and other MRI protocols has reportedly improved the diagnostic accuracy of parotid tumors. This review article summarizes the current state of DWI in differentiating parotid tumors.

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.

Basal Cell Adenocarcinoma Arising from the Parotid Gland

Basal cell adenocarcinoma (BCAC) is a rare malignant tumor of the salivary glands, representing 1-2% of salivary gland neoplasms. It is considered a low-grade tumor, often associated with a good prognosis. We report a case of a 60-year-old man with 3-month history of a growing, painless mass in the right ascending ramus of the mandible. Ultrasound and CT scan showed an asymmetry between parotid glands, depicting a nodular structure on the right side. A parotid fine needle aspiration cytology revealed neoplastic cells suggestive of adenoid cystic carcinoma. The patient underwent a total parotidectomy with lymph node dissection. Histopathology result was reported as BCAC. The patient concluded adjuvant radiotherapy and continued follow-up surveillance without evidence of relapse. The adjuvant approach in this case was decided by a multidisciplinary team given the absence of classically known risk factors. We highlight the importance of considering BCAC in the differential diagnosis in salivary gland tumors.

Assessment of a limited-access parotidectomy technique's complications and scar characteristics - A cohort study

OBJECTIVE

Parotidectomy is the treatment of choice for benign tumors of the parotid gland, with the modified Blair incision most commonly utilized. This retrospective analysis aimed to determine the incidence of complications and assess the relationship between the mass and scar characteristics, in patients who had undergone parotidectomy.

MATERIALS AND METHODS

The scar characteristics of patients who had undergone parotidectomy for benign neoplasms at our medical center between 2013 and 2019 were evaluated.

RESULTS

Overall, 49 patients met the inclusion criteria, of whom 33 agreed to participate in the study. The mean patient age was 52.8 years; 57.5% were males. No correlation was identified between the parotid mass size or location and scar type or length. The most common complications in this study were similar to those reported in the literature.

CONCLUSION

The results of this study suggest that the smaller, tailored modified Blair incision for parotidectomy does not increase complication rates. Future studies with larger cohorts should be conducted to further assess the potential benefits of tailored incision size during modified Blair parotidectomies.

Machine learning-based radiomics for histological classification of parotid tumors using morphological MRI: a comparative study

OBJECTIVES

To evaluate the effectiveness of machine learning models based on morphological magnetic resonance imaging (MRI) radiomics in the classification of parotid tumors.

METHODS

In total, 298 patients with parotid tumors were randomly assigned to a training and test set at a ratio of 7:3. Radiomics features were extracted from the morphological MRI images and screened using the Select K Best and LASSO algorithm. Three-step machine learning models with XGBoost, SVM, and DT algorithms were developed to classify the parotid neoplasms into four subtypes. The ROC curve was used to measure the performance in each step. Diagnostic confusion matrices of these models were calculated for the test cohort and compared with those of the radiologists.

RESULTS

Six, twelve, and eight optimal features were selected in each step of the three-step process, respectively. XGBoost produced the highest area under the curve (AUC) for all three steps in the training cohort (0.857, 0.882, and 0.908, respectively), and for the first step in the test cohort (0.826), but produced slightly lower AUCs than SVM in the latter two steps in the test cohort (0.817 vs. 0.833, and 0.789 vs. 0.821, respectively). The total accuracies of XGBoost and SVM in the confusion matrices (70.8% and 59.6%) outperformed those of DT and the radiologist (46.1% and 49.2%).

CONCLUSION

This study demonstrated that machine learning models based on morphological MRI radiomics might be an assistive tool for parotid tumor classification, especially for preliminary screening in absence of more advanced scanning sequences, such as DWI.

KEY POINTS

• Machine learning algorithms combined with morphological MRI radiomics could be useful in the preliminary classification of parotid tumors. • XGBoost algorithm performed better than SVM and DT in subtype differentiation of parotid tumors, while DT seemed to have a poor validation performance. • Using morphological MRI only, the XGBoost and SVM algorithms outperformed radiologists in the four-type classification task for parotid tumors, thus making these models a useful assistant diagnostic tool in clinical practice.

Adenoid cystic carcinoma of jugular foramen

Adenoid cystic carcinoma is a slowly growing malignant tumor with high local recurrence, perineural and vascular invasion. This tumor might arise from the glands of upper respiratory tract and oral cavity (eg, salivary or serous or mucous). Here we report the case of a 65-year-old woman who was referred to our unit for left retro-auricular radiating pain with trigger points and frontal headache since 6 months. There was no involvement of cranial nerves. Imaging screening using MRI, Positron emission tomography with 2-[fluorine-18] fluoro-2-deoxy-D-glucose, Gallium-68 DOTA-Phe1-Tyr3-Octreotide (68Ga DOTATOC) Positron emission tomography-CT suggested a suspicion of schwannoma or paraganglioma of the jugular foramen. However, the CT-guided biopsy revealed presence of adenoid cystic carcinoma. These warrants performing mandatory histological analysis combined with imaging screening suspicion of schwannoma or paraganglioma.

The role of perineural invasion in parotid malignancy outcomes: A systematic review and meta-analysis

PURPOSE

At present, perineural invasion is used as a histologic indicator of aggressive salivary gland disease. In other head and neck malignancies, perineural invasion impacts staging of cancer lesions and therefore affects treatment options.

OBJECTIVE

To compare survival outcomes in primary parotid malignancies with and without perineural invasion.A systematic review pooled data from the scientific literature in patients with any primary parotid malignancy to investigate the prognosis of those with perineural invasion.

DATA SOURCES

PubMed (Medline), Scopus and Cochrane databases were queried from inception to July 2020 without any initial search constraints. Additional publications were included from review of pertinent articles.

STUDY SELECTION

Our inclusion criteria included primary parotid cancers with reported perineural invasion on survival outcomes. Exclusion criteria were non-English language text, non-human studies, reviews, textbooks, abstracts, case reports and case series. Two authors independently reviewed articles for inclusion. Of the initial 465 records, 83 articles were reviewed in full to yield a final collection of 14 studies.

DATA EXTRACTION AND SYNTHESIS

PRISMA-p guidelines were used in the reporting of our studies. A MOOSE Checklist was also used. MINORS criteria were applied to assess risk of bias. Random-effects models were used to estimate pooled effect sizes. No institutional review board review was needed for our study.

MAIN OUTCOMES AND MEASURES

Primary study outcomes were set prior to data collection and included overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS) and distant-metastasis-free survival (DMFS) in patients with and without perineural invasion.

RESULTS

Fourteen studies contributed to this meta-analysis. Compared to patients without perineural invasion, the pooled rate of mortality (HR = 3.64), time to recurrence (HR = 3.56), disease-specific mortality (HR = 2.77) and distant metastasis (HR = 3.84) was significantly higher for patients with PNI (all p <.001). Controlling for perineural invasion status, no moderator was associated with these survival outcomes (all p >.05). Given the clinical severity of perineural invasion, few studies were null as shown in a panel of publication bias plots.

CONCLUSION

Perineural invasion portends a poor survival outcome in patients with parotid malignancies.

LEVEL OF EVIDENCE: 1

Histogram analysis of dynamic contrast-enhanced magnetic resonance imaging in the differential diagnosis of parotid tumors

Objective

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) histograms were used to investigate whether their parameters can distinguish between benign and malignant parotid gland tumors and further differentiate tumor subgroups.

Materials and methods

A total of 117 patients (32 malignant and 85 benign) who had undergone DCE-MRI for pretreatment evaluation were retrospectively included. Histogram parameters including mean, median, entropy, skewness, kurtosis and 10th, 90th percentiles were calculated from time to peak (TTP) (s), wash in rate (WIR) (l/s), wash out rate (WOR) (l/s), and maximum relative enhancement (MRE) (%) mono-exponential models. The Mann–Whitney U test was used to compare the differences between the benign and malignant groups. The diagnostic value of each significant parameter was determined on Receiver operating characteristic (ROC) analysis. Multivariate stepwise logistic regression analysis was used to identify the independent predictors of the different tumor groups.

Results

For both the benign and malignant groups and the comparisons among the subgroups, the parameters of TTP and MRE showed better performance among the various parameters. WOR can be used as an indicator to distinguish Warthin’s tumors from other tumors. Warthin’s tumors showed significantly lower values on 10th MRE and significantly higher values on skewness TTP and 10th WOR, and the combination of 10th MRE, skewness TTP and 10th WOR showed optimal diagnostic performance (AUC, 0.971) and provided 93.12% sensitivity and 96.70% specificity. After Warthin’s tumors were removed from among the benign tumors, malignant parotid tumors showed significantly lower values on the 10th TTP (AUC, 0.847; sensitivity 90.62%; specificity 69.09%; P < 0.05) and higher values on skewness MRE (AUC, 0.777; sensitivity 71.87%; specificity 76.36%; P < 0.05).

Conclusion

DCE-MRI histogram parameters, especially TTP and MRE parameters, show promise as effective indicators for identifying and classifying parotid tumors. Entropy TTP and kurtosis MRE were found to be independent differentiating variables for malignant parotid gland tumors. The 10th WOR can be used as an indicator to distinguish Warthin’s tumors from other tumors.

Results from a series of 58 cases

The aim of the study was to evaluate the efficacy and preliminary outcomes of using a postauricular-groove approach without endoscopic assistance for the excision of parotid tumors. Patients who underwent parotidectomy using a postauricular-groove incision were selected for this study. For patients in which parotidectomy was difficult, namely, for tumors located in the deep lobe area, the parotid gland sternocleidomastoid space was fully utilized, and the tumor was resected from the posterior plane. A total of fifty-eight patients with parotid tumor were enrolled and divided into superior lobe group (n = 46) and deep lobe group (n = 12). The difference in operation time (94 vs 119 min) and postoperative drainage (20.18 vs 45.33 mL) was statistically significant between the tumors in the superficial and deep lobes. However, postoperative cosmetic VAS score was 10 (extremely satisfied) for all patients. The incidence of transient facial nerve paralysis was comparable (8.7% vs 16.7%), and all of them resolved spontaneously within 3 months. No recurrence of tumors was found in either group in the median follow-up interval of 26.45 months (range 22.2-35.3 months), which was comparable to the result using the conventional "S" approach. After making full use of the parotid gland sternocleidomastoid space, the postauricular-groove approach demonstrated satisfactory facial nerve protection, as well as easy maneuverability without the risk of surgical complications for tumors located in the deep lobe area. Importantly, the postauricular-groove approach showed excellent cosmetic outcomes for all patients and should be considered an alternative approach for parotidectomy of selected cases.

The use of bipolar coagulation forceps prevented salivary fistula in patients with parotidectomy: a retrospective study

Background

Salivary fistula is a relatively common complication in patients who have undergone a parotidectomy. The purpose of this study was to investigate the effects of bipolar coagulation forceps use on salivary fistulas.

Methods

From March 2015 to June 2020, 177 patients who underwent a parotidectomy in the Department of Oral and Maxillofacial Surgery at the Second Xiangya Hospital of Central South University were recruited. The patients were divided into an experimental group and a control group based on whether bipolar coagulation forceps or sutures were used, respectively.

Results

The drainage output of the experimental group was significantly lower than that of the control group (p = 0.04). The duration of dressing pressure applied in the experimental group was significantly shorter than that in the control group (p = 0.0003). Moreover, the incidence of salivary fistula in the experimental group (9.8%, 8/82) was notably lower than that in the control group (34.7%, 33/95) (p < 0.0001). In the logistic regression model for salivary fistula development, both the use of bipolar coagulation forceps (p = 0.0021) and drainage output (p = 0.0237) were associated with the presence of salivary fistulas.

Conclusions

Our findings indicate that the use of bipolar coagulation forceps decreases the incidence of salivary fistula in patients who have undergone a parotidectomy. The use of bipolar coagulation forceps is a safe, effective, and convenient method to prevent salivary fistulas in patients who undergo a parotidectomy.

Trial registration: Current Controlled Trials ChiCTR2100044722, Date: 26/03/2021, Retrospectively registered.

Quantitative dynamic contrast-enhanced MRI and readout segmentation of long variable echo-trains diffusion-weighted imaging in differentiating parotid gland tumors

PURPOSE

To evaluate the ability of quantitative dynamic contrast-enhanced (DCE)-MRI and readout segmentation of long variable echo-trains diffusion-weighted imaging (RESOLVE-DWI) in differentiating parotid tumors (PTs) with different histological types.

METHODS

In this retrospective study, 123 patients with 145 histologically proven PTs who underwent both RESOLVE-DWI and DCE-MRI were enrolled including 51 pleomorphic adenomas (PAs), 52 Warthin's tumors (WTs), 27 other benign neoplasms (OBNs), and 15 malignant tumors (MTs). Quantitative parameters of DCE-MRI (K^trans, K_ep, and V_e) and the apparent diffusion coefficient (ADC) of lesions were calculated and analyzed. Kruskal-Wallis tests with Dunn-Bonferroni correction, logistic regression analyses, and receiver operating characteristic curve were used for statistical analyses.

RESULTS

PAs exhibited a lowest K^trans among these four PTs. WTs demonstrated the highest K_ep and lowest V_e values. WTs and MTs showed lower ADC_min values than PAs and OBNs. The combination of K_ep and V_e provided 98.1% sensitivity, 85% specificity, and 98.7% accuracy for differentiating WTs from the other three PTs. The ADC_min cutoff value of ≤ 0.826 yielded 80.0% sensitivity, 92.3% specificity, and 90.3% accuracy for the differentiation of MTs from PAs and OBNs. K^trans with a cutoff value of ≤ 0.185 achieved a sensitivity, specificity, and accuracy of 84.3, 70.4, and 79.5%, respectively, for discriminating PAs from OBNs.

CONCLUSION

The combination of quantitative DCE-MRI and RESOLVE-DWI is beneficial for characterizing four histological types of PTs.

Effective surgical management of anterior tumors of the parotid gland: Main trunk method vs. peripheral Smethod

OBJECTIVE

Several surgical procedures have been proposed for tumors in the anterior parotid gland. Although the standard approach to other parotid tumors is generally also used for anterior tumors, handling of the facial nerve has not been addressed in any previous reports.

METHODS

A total of 654 patients with benign parotid tumors who underwent surgery in our department were classified into anterior (AT), middle (MT), and posterior tumor (PT) groups according to tumor location. Clinical characteristics, histopathological types, and frequency of postoperative transient facial palsy were examined. In the AT group, two surgical methods were compared, which were the main trunk method (MTM) and the peripheral method (PM).

RESULTS

172 patients were included in the AT group, 175 in the MT group, and 307 in the PT group. The AT group showed significant female predominance and a higher percentage of deep lobe tumors than the PT group. There was no significant difference in the rate of postoperative transient facial palsy among the AT (MTM), MT, and PT groups. The PM had a significantly shorter operating time and lower rate of transient facial palsy than the MTM.

CONCLUSION

The PM for AT was considered a useful surgical method from the standpoints of postoperative complications and operating time. In the PM, a wide operating field made identification of the facial nerve easier.

Symptoms and signs of parotid tumors and their value for diagnosis and prognosis: a 20-year review at a single institution

BACKGROUND

Detailed clinical features other than parotid mass have not been investigated in detail for parotid tumors. Symptoms and signs are useful for the differentiation of benign versus malignant, and may also be of value to determine the grade of malignancy and histological type as well as the assessment of prognosis.

METHODS

We reviewed symptoms and signs of 965 patients with benign tumors and 200 patients with malignant tumors. Symptoms and signs included pain/tenderness, adhesion to surrounding tissues, and facial nerve palsy. We reviewed the incidence in benign and malignant tumors, in histological type of benign tumors, and in grade and histology of malignant tumors. For each symptom or sign, covariates were analyzed, and their correlation with the prognosis was investigated.

RESULTS

The incidence of symptoms and signs was significantly higher in malignant than benign tumors, and more frequent in higher grade of malignancy. Facial nerve palsy was observed in 18.0% of malignant tumor cases, while none occurred in benign tumor cases. Pain/tenderness was more commonly observed in adenoid cystic carcinoma, while adhesion to surrounding tissues and facial nerve palsy were most frequently noted in salivary duct carcinoma. The prognosis of patients with these symptoms and signs was significantly poor.

CONCLUSION

A detailed investigation of symptoms and signs in parotid gland tumors is the first step that leads to the diagnosis of malignant tumors. Symptoms and signs are also useful for estimating the grade of malignancy and histological type, and they are important information for predicting prognosis.

Metastases of Cutaneous Squamous Cell Carcinoma Seem to be the Most Frequent Malignancies in the Parotid Gland: A Hospital-Based Study From a Salivary Gland Center

Malignant parotid tumors account for approximately 20% of all parotid lesions. In addition to the various primary parotid lesions there are secondary parotid malignancies, such as metastases or lymphomas. Data on histopathological distribution of all malignancies-including secondary parotid lesions-is limited. Recent evidence indicated a rising surgical incidence of secondary parotid malignancies. This study aims to review the distribution of malignancies in parotid resections from a salivary gland center. A retrospective review of prospectively collected data for all patients who had received parotidectomy between 2014 and 2019 was performed. Histopathological distribution was displayed separately for all parotid malignancies and for primary parotid malignancies. Further, patients` characteristics were compared between benign and malignant parotid lesions and between the two most common malignant parotid lesions. Out of 777 patients, 614 (78.9%) patients had a benign and 164 (21.1%) patients had a malignant parotid lesion. The most common parotid malignancy was metastatic cutaneous squamous cell carcinoma (cSCC) accounting for 35.4% of all parotid malignancies. 71.5% of all malignant lesions were secondary malignancies. Patients with metastatic cSCC were significantly older (p < 0.001) and significantly more likely to be male (p < 0.001) than patients with primary parotid malignancies. No significant difference was found when the lesion size of metastatic cSCC was compared to primary parotid malignancies (p = 0.216). The present study shows the high prevalence of secondary parotid malignancies in patients who had received parotidectomy. Furthermore, it confirms a rising surgical incidence of metastatic cSCC to the parotid gland in a series from a salivary gland center. At this time, parotid surgery for malignant lesions is more likely to be performed for metastases than for primary parotid malignancies.

Magnetic resonance image biomarkers improve differentiation of benign and malignant parotid tumors through diagnostic model analysis

OBJECTIVES

To explore the effectiveness of magnetic resonance image (MRI)-based biomarkers for identifying benign and malignant parotid tumors via diagnostic model analysis.

METHODS

This retrospective study included 109 patients (development cohort and validation cohort) who underwent MRI preoperatively, including T1- and T2-weighted images. Parameters based on 2D or 3D texture analysis were extracted from tumor lesions by MaZda software, fisher discriminant and bootstrap method were used to perform parameter reduction, diagnostic models with the selected biomarkers were established along with clinical data, model performance (discrimination and calibration) was furtherly evaluated by internal and external validation, decision curve analysis was applied to measure the improvement of clinical benefits.

RESULTS

S(5,5) Entrop, S(0,1) ASM, WavEnHH (s-4), S(1,1,0) Entropy and Perc.10% were significantly associated with the pathological diagnosis of parotid tumor (benign versus malignancy), when adding these biomarkers to the regression analysis, model performance significantly improved in the development cohort (likelihood-ratio-test; p < 0.05, with an increase of AUC from 0.72 (reference model) to 0.85), and these results were maintained in a small external validation cohort. Decision curve analysis indicated that clinical benefit was greater with the application of MRI-based biomarkers.

CONCLUSIONS

MRI-based texture analysis is proven to be an effective tool in differentiating benign and malignant parotid tumors, preoperative diagnosis was improved with the selected biomarkers compared to the reference model.

Ultrasound-guided ethanol sclerotherapy for non-surgical treatment of Warthin's tumor

BACKGROUND

Currently, the first line treatment for Warthin's tumor (WT) is parotidectomy. There is a paucity of data evaluating the safety and efficacy of non-surgical treatments for patients not amenable to surgery. Ultrasound guided ethanol sclerotherapy (UGES) has been successfully used for the management of lymphangiomans of the head and neck, thyroid nodules, and thyroid cysts. This is the first study to implement and assess the success of UGES for management of WT.

METHODS

We report two patients with WT, with a total of 3 masses, who underwent UGES. All procedures were performed in the clinic. The primary outcome measured was the tumor volume reduction rate (VRR), patient satisfaction, and complications observed at follow-up.

RESULTS

Both patients experienced a significant reduction in tumor size upon follow up. VRR for the three treated tumors were 67.30%, 98.32%, and 55.73%. Patient were very satisfied with the results and noted significant cosmetic improvement. No complications were observed at follow-up.

CONCLUSIONS

Ultrasound guided ethanol sclerotherapy may be a viable option for conservative treatment of Warthin's tumor in patients unsuitable or unwilling to undergo surgical resection.

Non-sebaceous Lymphadenoma of the Parotid Gland Mimicking a Pleomorphic Adenoma

Non-sebaceous lymphadenoma of the salivary glands is a rare benign lesion, first described in 1991. We present the case of a 54-year-old woman, with a right parotid mass. She underwent right superficial parotidectomy, and histopathology reported a non-sebaceous lymphadenoma due to an encapsulated lesion and multiple non-atypical epithelial inclusions without sebaceous differentiation. The etiology of non-sebaceous lymphadenoma is not yet understood, but it can arise predominantly from the parotid gland. Surgical excision is the treatment of choice.

A novel clinically-oriented classification of fine-needle aspiration cytology for salivary gland tumors: a 20-year retrospective analysis of 1175 patients

Background

When determining treatment strategy for a salivary gland tumor, assessing histology and malignancy grade before surgery is essential. Several new diagnostic classification systems for salivary gland cytology have recently been proposed. However, none incorporate histology and grade of malignancy.

Methods

We developed a new cytology classification system that incorporates histology and grade of malignancy of salivary gland tumors (OMC classification), consisting of 11 categories. Our OMC classification was applied to 1175 patients who had preoperative cytology and confirmed final pathological diagnosis available from the past 20 years at our hospital (benign tumor: 981 patients, malignant tumor: 194 patients).

Results

Based on the cytology, 729 patients (62.0%) had benign histology (Category 4–1), and 87 patients (7.4%) were diagnosed with grade of malignancy (Category 6–3 + 6–4). Based on the final pathological diagnosis, the accuracy rate of Category 4–1 and Category 6–3 + 6–4 of our classification system was 93.4% and 88.5%, respectively.

Conclusion

Based on the correct diagnosis rate, the inclusion of histology and grade of malignancy in the salivary gland cytology classification was considered feasible. Thus, the OMC classification system is considered a useful tool when determining the treatment strategy for a salivary gland tumor.

Effectiveness of intraoperative facial nerve monitoring and risk factors related to postoperative facial nerve paralysis in patients with benign parotid tumors: A 20-year study with 902 patients

OBJECTIVE

We examined the incidence, risk factors, and recovery time for postoperative facial nerve paralysis in patients with benign parotid tumors and also investigated the usefulness of intraoperative facial nerve monitoring (FNM).

METHODS

Subjects were 902 patients with benign parotid tumors. Univariate and multivariate analyses were conducted for risk factors of postoperative facial nerve paralysis. We investigated the relationship between intraoperative FNM and postoperative facial nerve paralysis, and the recovery time for postoperative facial nerve paralysis according to tumor site.

RESULTS

Postoperative facial nerve paralysis occurred in 179 (19.8%) of 902 patients. Among them, 15.1%, 15.8%, and 37.5% had tumors in the superficial lobe, lower pole, and deep lobe, respectively. Paralysis risk factors were deep tumors, large tumors, long operation times, extensive bleeding, and non-use of FNM. Multivariate analysis determined female patients, deep tumors, and long operation times as significant risk factors, and female patients and deep tumors had an odds ratio of nearly 2. Use of intraoperative FNM resulted in a significantly lower incidence of facial nerve paralysis and was particularly useful in patients with superficial lobe tumors. Time to recovery from facial nerve paralysis was 6 months in 88% of the patients.

CONCLUSION

The incidence of paralysis should be kept as low as possible to enhance the postoperative quality of life of patients. The use of intraoperative FNM significantly lowered the incidence of paralysis in female patients with superficial tumors.

Review of treatment modalities and outcomes of patients with basal cell adenocarcinoma

PURPOSE

This study summarizes the treatment modalities of basal cell adenocarcinoma (BCAC) of the parotid gland and subsequent outcome at a single institution to better define the treatment of this rare tumor.

MATERIAL AND METHODS

A retrospective review of patients treated for BCAC of the parotid gland from 1/01/1996 to 08/1/2018 was performed. Patients were identified using our institution's Cancer Registry.

RESULTS

A total of thirteen patients (46% female, median age of 56) treated for BCAC of the parotid gland were identified. Eight patients (57%) were staged as T1, four were staged as T2 (29%), and two were stage T4a (14%) due to tumor involvement of the facial nerve. None of the patients had nodal involvement or distant metastases. Three patients (21%) underwent radiation therapy ranging from 60-70Gy for positive margin or facial nerve involvement by tumor. Five patients (36%) underwent a neck dissection (ND) ranging from just a level IIb dissection up to levels IIa, IIb, and III with none of the nodes being positive for disease. The remainder of patients did not undergo a neck dissection. Follow-up was 8.1 ± 6.2 (mean ± SD) years with no local or regional recurrence at time of last follow-up in any patient cohort.

CONCLUSIONS

Our review suggests that elective neck dissections are not necessary following resection of T1/T2N0M0 basal cell adenocarcinoma for the prevention of local or regional recurrence. No longer performing neck dissections for T1/T2N0M0 BCAC would reduce the morbidity associated with the treatment of this rare parotid tumor.

Facelift Surgery Following Superficial Parotidectomy: Is it Safe?

INTRODUCTION

Patients who have previously undergone superficial parotidectomy may also seek facelift surgery for facial aging and rejuvenation. These patients present unique challenges compared to a standard facelift patient. Most concerning is the location of facial nerve branches, which may be superficial and displaced. In addition, significant contour deformities and abnormal scar patterns may be present. The purpose of the study is to review our series of patients and assess potential morbidity and safety of facelift surgery in superficial parotidectomy patients.

METHODS

A retrospective case series was performed reviewing all patients who underwent facelift surgery following superficial parotidectomy from 2000 to 2017. Data were collected for: postoperative facial nerve deficit, soft tissue contour and scar deformities, facelift technique, ancillary soft tissue augmentation procedures and pre- and postoperative photographs. An evidence-based treatment algorithm to address specific problems in this patient population was developed.

RESULTS

A total of seven patients were identified who underwent facelift surgery following parotidectomy. Patients underwent one of the standard SMAS procedure on the non-parotidectomy side, and surgical modifications were made to address the parotidectomy side; soft tissue augmentation was performed in two patients. Precautions to identify the facial nerve and prevent injury, including nerve monitoring and stimulation, were utilized in all seven patients. No permanent postoperative facial nerve injury was noted.

CONCLUSION

Facelift following superficial parotidectomy was safely performed in all cases. Special consideration should be given to contour deformities, facial nerve location and scar placement. However, if approached properly, these patients can still be considered as suitable candidates for facelift surgery.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The histogram analysis of apparent diffusion coefficient in differential diagnosis of parotid tumor

OBJECTIVES

Use apparent diffusion coefficient (ADC) histogram to investigate whether the parameters of ADC histogram can distinguish between benign and malignant tumors and further differentiate the tumor subgroups.

METHODS AND MATERIALS

This study retrospectively enrolls 161 patients with parotid gland tumors. Histogram parameters including mean, inhomogeneity, skewness, kurtosis and 10th, 25th, 50th, 75th, 90th percentiles are derived from ADC mono-exponential model. Mann-Whitney U test is used to compare the differences between benign and malignant groups. Kruskal-Wallis test with post-hoc Dunn-Bonferroni method is used for subgroup classification, then receiver operating characteristic curve analysis is performed in mean ADC value to obtain the appropriate cutoff values.

RESULTS

Except for kurtosis and 90th percentile, there are significant differences in all other ADC parameters between benign and malignant groups. In subgroup classification of benign tumors, there are significant differences in all ADC parameters between pleomorphic adenoma and Warthin's tumor (area under curve 0.988; sensitivity 93.8%; specificity 94.7%; all ps < 0.05). Pleomorphic adenoma has high value in mean than basal cell adenoma (area under curve 0.819; sensitivity 76.9%; specificity 76.9%; p < 0.05). Basal cell adenoma has high values in mean (area under curve 0.897; sensitivity 92.3%; specificity 78.9%; all ps < 0.05) and 10th, 25th, 50th percentiles than Warthin's tumor. In subgroup classification of malignant tumors, low-risk parotid carcinomas have higher values than hematolymphoid tumors in mean (area under curve 0.912; sensitivity 84.6%; specificity 100%, all ps < 0.05) and 10th, 25th percentiles.

CONCLUSION

ADC histogram parameters, especially mean and 10th, 25th percentiles, can potentially be an effective indicator for identifying and classifying parotid tumors.

Parotid Gland Carcinoma Masquerading as an Aural Polyp

INTRODUCTION

Parotid gland squamous cell carcinoma is an uncommon aggressive neoplasm with poor prognosis. Aural polyps are usually the presenting features of chronic suppurative otitis media, tuberculous otitis media, and adenoma or carcinoma. The malignant aural polyp is very rare. Parotid gland carcinoma masquerading as an aural polyp has rarely been described in the literature.

CASE REPORT

We report a case study of parotid squamous cell carcinoma in a 29-year-old male masquerading as an ear polyp.

CONCLUSION

Parotid gland primary squamous cell carcinoma is a rapidly advancing neoplasm which carries poor prognosis despite multimodality treatment. Diligent clinical and histopathological evaluation is imperative to discriminate this rare aggressive disease from the metastatic and other primary cancers of the parotid. A high index of suspicion is crucial in refractory aural polyps to arrive at early diagnosis.

A multiparametric analysis based on DCE-MRI to improve the accuracy of parotid tumor discrimination

BACKGROUND

Recently, semiquantitative time-intensity curve (TIC) analysis based on DCE-MRI and apparent diffusion coefficient (ADC) value-based diffusion-weighted imaging (DWI) were used to improve the diagnostic efficiency when diagnosing parotid tumors (PTs). However, quantitative DCE-MRI biomarkers have not been emphasized previously.

PURPOSE

To explore the diagnostic efficiency of perfusion parameters alone or in combination based on quantitative DCE-MRI and DWI in the differential diagnosis of PTs.

METHODS

In total, 112 patients with parotid masses were prospectively recruited in our hospital from August 2013 to March 2017. All patients were evaluated with DCE-MRI and DWI before surgery. TIC and quantitative parameters based on DCE MRI and ADCs were analyzed. Receiver operating characteristic analysis and linear discriminant analysis (LDA) was used to determine their diagnostic performance.

RESULTS

In total, 87% (27/31) of pleomorphic adenoma (PA) showed type A TIC, 74% (65/88) of Warthin's tumors showed type B TIC, and 95% (19/20) of malignant tumors showed TIC type C. Pearson X² test showed a significant difference between TIC patterns in benign and malignant tumors (X² = 38.78, p < 0.001). ROC analysis revealed that ADC achieved the best diagnostic performance for distinguishing PA and Warthin's tumor from others, with area under the curve (AUC) values of 0.945 and 0.925 (p < 0.01), respectively. Furthermore, the TIC type was the only useful biomarker for distinguishing malignant from benign PTs, with an AUC of 0.846 (p < 0.01). Concerning the accuracy of the combined application of multiple parameters of DCE-MRI and ADC values, a combination of TIC pattern and extracellular volume ratio (Ve) provided the best results among five protocols, producing the highest accuracy of 0.75, followed by the combined use of the TIC pattern and ADC (accuracy was 0.70).

CONCLUSION

TIC pattern in combination with the Ve biomarker based on DCE-MRI could achieve optimal diagnostic accuracy in the differential diagnosis of PTs.

Retrograde parotidectomy under local anesthesia for benign, malignant, and inflammatory lesions

OBJECTIVE

To report the patient selection, surgical technique, and outcomes of parotidectomy using local anesthesia under monitored anesthesia care (MAC).

METHODS

A retrospective chart review was performed for patients undergoing parotidectomy under local anesthesia at an academic head and neck surgery center.

RESULTS

Six patients deemed high risk for general anesthesia (GA) due to medical comorbidities or with a strong preference to avoid GA underwent parotidectomy using local anesthesia and MAC. Parotidectomy was performed for several indications, including benign tumors, malignant tumors, and chronic sialadenitis. Mean age of patients was 78.0 ± 7.9 years, and all had an American Society of Anesthesia score ≥ 2 and Charlson comorbidity index ≥4. Mean operative time was 102.8 ± 38.3 min, comparable to that of parotidectomy under general anesthesia. No major complications occurred. Minor complications included three cases of temporary postoperative facial nerve weakness limited to 1-2 lower division branches. At most recent follow up (10 to 48 months), all patients were medically stable and disease free.

CONCLUSION

In carefully selected patients, parotidectomy under local anesthesia is a viable treatment alternative that can be offered to patients. Successful outcomes require preoperative counseling, meticulous technique, and close collaboration with anesthesia colleagues.

Intraductal pseudopodia in pleomorphic adenoma of parotid gland

Pleomorphic adenoma is the most common salivary gland tumor. Pseudopodia are finger-like projections extending beyond the tumor capsule, seen in pleomorphic adenoma. If not resected completely, these pseudopodia may increase the risk of recurrence after excision of pleomorphic adenoma. While performing a total conservative parotidectomy for the pleomorphic adenoma of the parotid gland, we encountered tumor in the Stensen's duct. On pathological examination, the tumor was not involving the wall of the duct but was passing through the lumen, like a pseudopod. During parotidectomy, the surgeon should inspect the lumen of parotid duct for the presence of any tumor. Pseudopodia of pleomorphic adenoma may extend into the lumen and if not addressed adequately may lead to recurrence of the tumor.

A modified V-shaped incision combined with superficial musculo-aponeurotic system flap for parotidectomy

BACKGROUND

V-shaped incision (VSI) for parotidectomy had been introduced for cosmetic purpose. Despite having aesthetic superiority, it required excessive retraction or an additional hairline incision for adequate surgical exposure. To overcome these problems, we conceptualized a modified VSI approach combined with a separate superficial musculo-aponeurotic system flap.

AIMS

This study aimed to propose this approach and evaluate its technical feasibility and efficacy for excision of parotid tumors.

MATERIALS AND METHODS

This is a prospective, nonrandomized study involving 74 patients with small-to-medium (<4 cm), benign parotid tumors located superficially. The patients were divided into two groups based on the incision techniques used: modified VSI and modified Blair incision (MBI). The clinical outcomes of both approaches for parotidectomy were analyzed.

RESULTS

Thirty-four patients underwent modified VSI approach, while 40 underwent MBI. All parotidectomies with modified VSI were successfully completed without any further incision, and no facial nerve injury or intraoperative tumor rupture complication was reported. There were no significant differences in the complications between both approaches, such as hematoma, infection, wound dehiscence, skin necrosis, sialocele, or sensory disturbance. The modified VSI group showed better cosmetic satisfaction results than did the MBI group (9.2 and 7.8, respectively; p < .001).

CONCLUSIONS AND SIGNIFICANCE

The modified VSI approach is safe and feasible for small-to-medium benign parotid tumors. This approach could be a possible option for patients with a high cosmetic demand.

LEVEL OF EVIDENCE

4.

STUDY DESIGN

Prospective pilot study.

The preventive effect of decellularized pericardial patch against Frey's syndrome following the superficial parotidectomy

PURPOSE

This study aimed to investigate the feasibility of adopting the ThormalGEN surgical patch (a porcine decellularized pericardial patch) in the superficial parotidectomy to prevent postoperative Frey's syndrome in patients with benign parotid tumor.

MATERIALS AND METHODS

A total of 59 patients with benign parotid tumor undergoing superficial parotidectomy between April 2016 and January 2017 were enrolled, and divided into the ThormalGEN group (n = 37) and the control group (n = 22) based on their willingness to have the ThormalGEN surgical patch used in the superficial parotidectomy. At 6 months postoperation, the incidences of postoperative complications and Frey's syndrome were assessed by subjective assessment (patient self-assessment) and objective assessment (starch-iodine test), respectively. The risk factor of Frey's syndrome was analyzed by the multivariate logistic regression model.

RESULTS

The starch-iodine test, for objective assessment, showed that the ThormalGEN group had a significantly lower incidence of Frey's syndrome than the control group (8.11% vs. 40.91%, p = 006). However, in the patient self-assessment, there was no significant difference in the incidence of Frey's syndrome between groups (8.11% [3/37] vs. 13.64% [3/22], p = 0.4968). The incidences of postoperative complications were not significantly different between group (all p > 0.05). Two patients (5.41%) in the ThormalGEN group had salivary fistula. Multivariate logistic regression analysis showed that the ThormalGEN group had a significantly lower risk of Frey's syndrome than the control group (odds ratio = 0.11, 95% confidence interval = 0.02-0.51, p < 0.01).

CONCLUSION

These results suggest that the ThormalGEN surgical patch can effectively reduce the incidence of Frey's syndrome following superficial parotidectomy in patients with benign parotid tumor, and that this patch has a good safety and biocompatibility profile.

Management of the facial nerve in parotid cancer: preservation or resection and reconstruction

PURPOSE

Management of the facial nerve is instrumental in the surgical treatment of parotid cancer.

METHODS

A literature search was conducted using PubMed and ScienceDirect database. A total of 195 articles were finally included into the analysis, based on relevance, scientific evidence and actuality.

RESULTS

In the majority of cases the facial nerve is not involved by tumor. In these cases, identification and preservation of the nerve, in addition to complete tumor removal, are essential for successful surgery. When the nerve is infiltrated by tumor, the affected portion of the nerve must be resected as part of radical parotidectomy. Primary nerve reconstruction or other reanimation techniques give the best long-term functional and cosmetic results. A comprehensive diagnostic evaluation with current imaging and electrophysiological studies will provide the surgeon with the best knowledge of the relationship of the facial nerve to the tumor. Several standardized methods are helpful in finding, dissecting and preserving the nerve during parotid cancer surgery. When radical parotidectomy is indicated, the initial diagnostic work-up can assist in defining the need for adjuvant postoperative therapy and facial reanimation. The aim of rehabilitation is to restore tone, symmetry, and movement to the paralyzed face.

CONCLUSIONS

The surgical management of facial paralysis has undergone many improvements in recent years. This review gives an overview of recent advances in the diagnostic work-up, surgical techniques and any necessary rehabilitation of the facial nerve in parotid cancer surgery.

National trends in inpatient parotidectomy: A fourteen-year retrospective analysis

PURPOSE

Operating room (OR) procedures represent one quarter of hospitalizations, yet OR-related stays account for nearly 50% of hospital costs. Understanding trends in inpatient parotidectomy, associated charges, and key outcomes including length of stay is imperative in the era of evolving health reform.

MATERIALS AND METHODS

The Nationwide Inpatient Sample (NIS) was queried for patients who underwent inpatient parotidectomy (ICD9-CM procedure code 26.31 and 26.32) between 2001 and 2014. Patient demographics, co-morbidities, hospital characteristics and outcomes including length of stay (LOS) and hospital charges were assessed.

RESULTS

A total of 66,914 parotidectomies were performed in the inpatient setting between 2001 and 2014. The volume of inpatient parotidectomy decreased steadily by 48% over the study period (7375 procedures in 2001 to 3530 procedures in 2014). Average LOS increased from 1.8 days in 2001 to 2.5 days in 2014. Total charges increased from $17,072 in 2001 to $55,929 in 2014. In 2014, the majority of inpatient parotidectomies were performed in a teaching hospital (87%) and among patients who were older than 65 years (48.1%). In 2001, only 35.4% of patients who underwent parotidectomy were older than age 65, and relatively fewer surgeries were performed at teaching hospitals (63.1%).

CONCLUSIONS

Inpatient parotidectomy in the United States has evolved over the past fourteen years. Notable trends include a nearly 50% reduction of inpatient surgery, doubling in LOS, tripling of hospital charges and predominance of elderly patients with malignant disease. These results provide insight into inpatient parotid lesion management.

Contrast-Enhanced CT with Knowledge-Based Iterative Model Reconstruction for the Evaluation of Parotid Gland Tumors: A Feasibility Study

Objective

The purpose of this study was to determine the diagnostic utility of low-dose CT with knowledge-based iterative model reconstruction (IMR) for the evaluation of parotid gland tumors.

Materials and Methods

This prospective study included 42 consecutive patients who had undergone low-dose contrast-enhanced CT for the evaluation of suspected parotid gland tumors. Prior or subsequent non-low-dose CT scans within 12 months were available in 10 of the participants. Background noise (BN), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were compared between non-low-dose CT images and images generated using filtered back projection (FBP), hybrid iterative reconstruction (iDose⁴; Philips Healthcare), and knowledge-based IMR. Subjective image quality was rated by two radiologists using five-point grading scales to assess the overall image quality, delineation of lesion contour, image sharpness, and noise.

Results

With the IMR algorithm, background noise (IMR, 4.24 ± 3.77; iDose⁴, 8.77 ± 3.85; FBP, 11.73 ± 4.06; p = 0.037 [IMR vs. iDose⁴] and p < 0.001 [IMR vs. FBP]) was significantly lower and SNR (IMR, 23.93 ± 7.49; iDose⁴, 10.20 ± 3.29; FBP, 7.33 ± 2.03; p = 0.011 [IMR vs. iDose⁴] and p < 0.001 [IMR vs. FBP]) was significantly higher compared with the other two algorithms. The CNR was also significantly higher with the IMR compared with the FBP (25.76 ± 11.88 vs. 9.02 ± 3.18, p < 0.001). There was no significant difference in BN, SNR, and CNR between low-dose CT with the IMR algorithm and non-low-dose CT. Subjective image analysis revealed that IMR-generated low-dose CT images showed significantly better overall image quality and delineation of lesion contour with lesser noise, compared with those generated using FBP by both reviewers 1 and 2 (4 vs. 3; 4 vs. 3; and 3–4 vs. 2; p < 0.05 for all pairs), although there was no significant difference in subjective image quality scores between IMR-generated low-dose CT and non-low-dose CT images.

Conclusion

Iterative model reconstruction-generated low-dose CT is an alternative to standard non-low-dose CT without significantly affecting image quality for the evaluation of parotid gland tumors.

Diagnostic accuracy of magnetic resonance imaging techniques for parotid tumors, a systematic review and meta-analysis

OBJECTIVE

To assess the added benefit of combining different MRI techniques for preoperative diagnosis of parotid tumors when compared to conventional MRI and advanced MRI techniques alone with meta-analysis.

METHODS

A comprehensive PubMed electronic database search was performed for original diagnostic studies up to July 2017. The methodologic quality of each study was evaluated by two independent reviewers who used the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Statistical analysis included pooling of sensitivity and specificity with 95% confidence intervals (CI). All analyses were conducted using STATA (version 12.0), RevMan (version 5.2), and Meta-Disc 1.4 software programs.

RESULTS

Pooled sensitivity and specificity of conventional MRI, diffusion weighted imaging (DWI), dynamic contrast enhanced (DCE) and the above combination were 76% (95%CI)/91% (95%CI)/80% (95%CI)/86% (95%CI) and 83% (95%CI)/56% (95%CI)/90% (95%CI)/90% (95%CI).

CONCLUSION

Conventional MRI combined with DWI and DCE showed higher diagnostic accuracy than conventional or advanced MRI alone, supporting their use in parotid tumors diagnosis.

Brain metastasis of carcinoma ex pleomorphic adenoma of the parotid gland: case report and review of the literature

We present an extremely infrequent case of brain metastasis of a parotid tumor. To our knowledge, this is the second case reported of a brain metastasis of a malignant parotid tumor, carcinoma ex pleomorphic adenoma. Pleomorphic adenoma represents 60% of tumors of the parotid gland, and although it is a benign tumor, it can transform into carcinoma ex pleomorphic adenoma in 5% of cases, one of the most aggressive neoplasms of the salivary glands. We want to note the need for an accurate diagnostic. Thanks to aggressive surgical management, our patient survived more than 1½ years.

Parotid Gland Tumors and the Facial Nerve

Various types of parotid gland tumors are discussed from nonneoplastic to both benign and malignant neoplasms. The anatomic relationship of the facial nerve is discussed as it exits the stylomastoid foramen and courses through the parotid gland. The effect of certain tumors on facial nerve function is also characterized. Details on which types of parotid tumors are more likely to affect facial nerve function and different prognostic predictors of return to function are evaluated. In addition, the prognostic value of tumor size and histologic type of parotid tumor is included.

A new electroneurography as a prognostic tool for marginal mandibular nerve paralysis after parotid gland surgery: A preliminary evaluation

OBJECTIVE

Marginal mandibular nerve paralysis is the most frequent complication of benign parotid tumor surgery and results in cosmetic deformity. The purpose of this study was to develop a new electroneurography method for marginal mandibular nerve paralysis using electroneurography (ENoG) and judge its usefulness for clinical practice.

METHODS

Twenty-seven patients who underwent surgery for benign parotid tumor were enrolled. We proposed and use the mandibular angle method, in which the recording electrode was placed on the skin above the depressor anguli oris muscle while the reference electrode was placed on the skin of the parietal region, and percutaneous electrical stimulation was applied to enclose the mandibular angle that could measure the function of the marginal mandibular nerve solely. Preoperative and postoperative ENoG values were compared in paralytic and non-paralytic patients.

RESULTS

The mean postoperative ENoG value (35.0%) was lower than the preoperative value (90.5%) in paralytic patients, whereas no difference was observed between preoperative (79.3%) and postoperative (69.5%) ENoG values in non-paralytic patients.

CONCLUSION

A new ENoG method (mandibular angle method) was thought to reflect marginal mandibular nerve injury and might be useful for determining the likelihood of paralysis.

[Diagnosis and treatment of the tumors of the parotid region in Pediatrics: cohort]

INTRODUCTION

Parotid tumors are rare in children and usually have multiple differential diagnoses that require different diagnostic and treatment methods.

MATERIAL AND METHODS

Retrospective cohort study of all consecutive pediatric patients with parotid tumors that were treated in Pediatric Surgery Service of Hospital Italiano de Buenos Aires.

RESULTS

Twenty-two patients with parotid tumors were included and 72% (n=16) were female patients. The median age was 10 years (range: prenatal to 19 years). Imaging studies: ultrasound, CT and MRI. Diagnostic methods: needle or open biopsy (14), biopsy of lymph nodes (3), imaging (4), blood test (1). Treatment: surgical resection (12), medical treatment (7), sclerotherapy (2). Diverse histological diagnosis were obtained: pleomorphic adenoma (4), infantile hemangioma (4), PNET (2), low flow vascular malformation (2), Castleman's disease (1), schwannoma (1), neuroblastoma (1), alveolar rhabdomyosarcoma (1), mucoepidermoid carcinoma (1) RICH (Rapidly Involuting Congenital Hemangioma) (1), granulomatous disease (1), reactive adenitis (1), parotid cyst (1), ALL (Acute Lymphoblastic Leukemia) (1). Follow-up (42,5 months): 18 patients are free of disease, 3 are currently under medical treatment and 1 died.

CONCLUSIONS

Our series shows the diversity that parotid tumor can present in pediatric population and is consistent with the literature there the incidence of benign lesions are predominant. However, it is difficult to predict risk of malignancy. An exhaustive diagnosis is important, using complementary methods and biopsy whenever that is necessary.

Primary unclassified sarcoma of the parotid gland: a case of diagnostic and therapeutic challenge

Malignant salivary gland sarcomas represent a clinically and histologically diagnostic challenge. Primary unclassified sarcomas of the parotid gland consist a rare salivary gland tumor. We report an unusual case of such a tumor, which occurred in the right parotid gland of a 54-year-old male and presented as an asymptomatic painless mass. The pathologoanatomical examination revealed a rhabdoid large-cell unclassified sarcoma. The patient was treated with superficial parotidectomy and adjuvant radiotherapy. No recurrence was noted in a 10-year follow-up period. Due to the rare occurrence of primary unclassified sarcomas, there is no evidence-based treatment of choice. An optimal approach is best planned in a multidisciplinary setting, taking into consideration the resectability of the tumor, individual patient characteristics, presence of local or distant metastatic activity, local infiltrative behavior and tumor stage. A close follow-up of the patient is strongly recommended.

Patterns and surgical significance of facial nerve branching within the parotid gland in 43 cases

PURPOSE

Different patterns of facial nerve branching within the parotid gland were detected, and these anatomical variations may affect the treatment approaches and outcomes of surgery. The aim of this study was to identify the patterns of facial nerve branching with the parotid gland and their importance in surgical procedures.

MATERIALS AND METHODS

A total of 43 patients undergoing surgical treatments of parotid lesions were included in this study. Each patient's demographic data and type of operation were recorded. In addition, the courses of the facial nerve within the gland were classified into six types according to their branching patterns and communication.

RESULTS

In all of the patients, the facial nerve consisted of one trunk separated into two divisions. Branching type III was the most common variety found (30.2 %) followed by type II (23.2 %), while type V represented the least frequent pattern (4.6 %).

CONCLUSION

It is essential for surgeons to become familiar with the different types of nerve morphologies in order to avoid morbidity and preserve the facial nerve during surgery. Variations and anastomosis can explain the different consequences of facial nerve injury that may occur after parotid surgery.

Small access postaural parotidectomy: an analysis of techniques, feasibility and safety

For cosmetic consideration of parotidectomy, the surgical approaches have evolved from Blair incision through modified facelift incision to postaural-hairline incision. The present study aims at evaluating the feasibility and safety of the new technique of postaural approach. Parotidectomy was performed with a 4-5 cm incision in the postaural sulcus. There were 69 patients who were assessed pre-operatively feasible for consideration of the postaural parotidectomy. There were 56 (81 %) patients who could have the postaural parotidectomy successfully without complications. The minimally invasive postaural approach is a further step in cosmetic consideration of parotidectomy. It is a feasible and safe approach for most small to medium size benign parotid tumors located in the mid and lower pole regions of the parotid gland.

A neglected giant parotid gland mass: excision and reconstruction with facial nerve preservation

Carcinoma ex pleomorphic adenoma (CXPA) is a malignant transformed variant of pleomorphic adenoma (PA). Generally it presents with a rapidly growing mass in the parotid gland within a preexisting PA or following surgical resection of PA. Mainstream treatment modality is surgical resection followed by radiotherapy if necessary. Facial nerve preservation and complete resection of the tumor are the main principles of the operation. Giant malignant derivates are not seen frequently and constitute a challenging task for surgeons to achieve the main principles of resection. Prognosis of CXPA is poor and aggressive treatment should be performed immediately after the diagnosis. We present a 82-year-old woman with a giant malignant parotid gland mass who was successfully treated with surgery without any facial nerve injury.

Long term quality of life in pediatric patients surviving parotid tumors

OBJECTIVE

To evaluate the long term quality of life in pediatric patients who have survived parotid tumors.

METHODS

A quality of life instrument, based on the principles of the University of Washington Quality of Life questionnaire, was specifically created for this study and sent to pediatric patients who had undergone a parotidectomy between 2000 and 2008.

RESULTS

The mean general health score was 3.45, which was deemed good to very good. The highest overall score in the group was 99.24. These results indicated that almost no patients complained of pain. Initially, 10 patients had reported that sensation was affected, but six of these cases recovered. Three (9.1%) patients reported a change in their appearance. Two patients (6.1%) reported surgical site depression and a further two (6.1%) reported scarring depression. Six (18.2%) patients reported facial nerve impairment during the early postoperative period, and four of these cases recovered. Two patients reported fistula during the early postoperative period, and but the symptoms were resolved after intervention. Frey's syndrome was reported by three (9.1%) patients.

CONCLUSION

Parotidectomy has a limited negative impact on pediatric patients' quality of life.