Accuracy of diagnosis of salivary gland tumors with the use of ultrasonography, computed tomography, and magnetic resonance imaging: a meta-analysis

Oncologic outcomes of the most prevalent major salivary gland cancers: retrospective cohort study from single center

BACKGROUND

The preoperative diagnosis of salivary gland cancer (SGC) is crucial for the application of appropriate treatment, particularly involving the extension of the resection.

METHODS

Retrospective search of medical database identified 116 patients treated surgically with malignant tumors of salivary gland between 2010 and 2020. Analysis included the demographical data, clinical course, type of surgical and adjuvant treatment, histology type and margin status, perivascular invasion (LVI), perineural invasion (PNI), metastatic lymph nodes (LN). Facial nerve function, recurrence-free and overall survival were evaluated. Adequate statistics were used for data analysis.

RESULTS

The final cohort included 63 SGC patients, with adenoid cystic carcinoma the most common pathological type (27%, n = 17), followed by adenocarcinoma (17.4% n = 11). T1 and T2 patients accounted for majority cases (n = 46). The lymph node metastases were confirmed with the histopathology in 31.7% (n = 20). Distant metastases were observed in 4.8% of cases (n = 3). 38% (n = 24) of SGC were treated selectively with surgery, 49.2% (n = 31) had postoperative radiotherapy and 15.9% (n = 10)-radio-chemotherapy. The final facial nerve function was impaired in 38% of patients. Mean overall survival (OS) for all patients was 108.7 (± 132.1) months, and was the most favorable for acinar cell carcinoma (118.9 ± 45.4) and the poorest for squamous cell carcinoma (44 ± 32). Cox regression analysis of disease-free survival and OS identified significant association only with patients' age over 65 years, the hazard ratio of 7.955 and 6.486, respectively.

CONCLUSIONS

The efficacy of treatment modalities for SGC should be verified with regard to the histopathological type, but also the patients' age should be taken into account.

Multispectral optoacoustic tomography of benign parotid tumors in vivo: a prospective observational pilot study

Parotid lumps are a heterogeneous group of mainly benign but also malignant tumors. Preoperative imaging does not allow a differentiation between tumor types. Multispectral optoacoustic tomography (MSOT) may improve the preoperative diagnostics. In this first prospective pilot trial the ability of MSOT to discriminate between the two most frequent benign parotid tumors, pleomorphic adenoma (PA) and Warthin tumor (WT) as well as to normal parotid tissue was explored. Six wavelengths (700, 730, 760, 800, 850, 900 nm) and the parameters deoxygenated (HbR), oxygenated (HbO2), total hemoglobin (HbT), and saturation of hemoglobin (sO2) were analyzed. Ten patients with PA and fourteen with WT were included (12/12 female/male; median age: 51 years). For PA, the mean values for all measured wave lengths as well as for the hemoglobin parameters were different for the tumors compared to the healthy parotid (all p < 0.05). The mean MSOT parameters were all significantly higher (all p < 0.05) in the WT compared to healthy parotid gland except for HbT and sO2. Comparing both tumors directly, the mean values of MSOT parameters were not different between PA and WT (all p > 0.05). Differences were seen for the maximal MSOT parameters. The maximal tumor values for 900 nm, HbR, HbT, and sO2 were lower in PA than in WT (all p < 0.05). This preliminary MSOT parotid tumor imaging study showed clear differences for PA or WT compared to healthy parotid tissue. Some MSOT characteristics of PA and WT were different but needed to be explored in larger studies.

Evaluation and management of dry mouth and its complications in rheumatology practice

INTRODUCTION

The symptom of dry mouth has multiple potential etiologies and can be a diagnostic clue to the presence of common systemic diseases encountered in rheumatology practice. The presence of decreased saliva flow (i.e. salivary hypofunction) defines a subset of dry mouth patients in whom there may be reversible drug effects, an iatrogenic insult such as head and neck irradiation, or a disease that directly involves the salivary glands (e.g. Sjögren's disease). The assessment of salivary hypofunction includes sialometry, salivary gland imaging, salivary gland biopsy, and an assessment for relevant systemic diseases. Optimal management of dry mouth requires accurate definition of its cause, followed by general measures that serve to alleviate its symptoms and prevent its complications.

AREAS COVERED

Through a literature search on xerostomia and salivary hypofunction, we provide an overview of the causes of dry mouth, highlight the potential impact of salivary hypofunction on oral and systemic health, detail routine evaluation methods and treatment strategies, and emphasize the importance of collaboration with oral health care providers.

EXPERT OPINION

Our Expert Opinion is provided on unmet needs in the management of dry mouth and relevant research progress in the field.

Sonographic and Cytological Evaluation of Salivary Gland Tumors

INTRODUCTION

Salivary gland tumours are relatively uncommon, but they have a multifaceted clinical presentation and varied morphological configuration. The investigations required for these tumours remain debatable. We conducted a study to determine the accuracy of various modalities used in salivary gland tumours.

METHODS

We enrolled 72 subjects, consisting of 44 females and 28 males, with a mean age of 40.93 ± 16.51 years (range: 15 to 79 years), suffering from various salivary gland tumours. The tumour distribution included 42 parotid gland tumours (58.33%), followed by 21 submandibular gland tumours (29.16%), three sublingual gland tumours (4.16%), and six minor salivary gland tumours (8.33%). These individuals were subjected to clinical examination, sonography, and fine needle aspiration cytology as per indications. The results of each modality were compared to surgical pathology to find sensitivity and accuracy.

RESULTS

The clinical examination was found to be least sensitive (83.8%) as compared to FNAC (97.6%), and ultrasound (100%). Ultrasound had the highest diagnostic accuracy (86.2%) as compared to clinical examination (80.6%) and FNAC (82.6%).

CONCLUSION

Although sonography was found to have the highest sensitivity and accuracy as compared to fine needle aspiration cytology and clinical examination, the difference was subtle, as both sonography and fine needle aspiration cytology had a statistically significant correlation with histopathology.

ACR Appropriateness Criteria® Staging and Post-Therapy Assessment of Head and Neck Cancer

Imaging of head and neck cancer at initial staging and as part of post-treatment surveillance is a key component of patient care as it guides treatment strategy and aids determination of prognosis. Head and neck cancer includes a heterogenous group of malignancies encompassing several anatomic sites and histologies, with squamous cell carcinoma the most common. Together this comprises the seventh most common cancer worldwide. At initial staging comprehensive imaging delineating the anatomic extent of the primary site, while also assessing the nodal involvement of the neck is necessary. The treatment of head and neck cancer often includes a combination of surgery, radiation, and chemotherapy. Post-treatment imaging is tailored for the evaluation of treatment response and early detection of local, locoregional, and distant recurrent tumor. Cross-sectional imaging with CT or MRI is recommended for the detailed anatomic delineation of the primary site. PET/CT provides complementary metabolic information and can map systemic involvement. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Diagnosis of Salivary Gland Tumors Using Transfer Learning with Fine-Tuning and Gradual Unfreezing

Ultrasound is the primary tool for evaluating salivary gland tumors (SGTs); however, tumor diagnosis currently relies on subjective features. This study aimed to establish an objective ultrasound diagnostic method using deep learning. We collected 446 benign and 223 malignant SGT ultrasound images in the training/validation set and 119 benign and 44 malignant SGT ultrasound images in the testing set. We trained convolutional neural network (CNN) models from scratch and employed transfer learning (TL) with fine-tuning and gradual unfreezing to classify malignant and benign SGTs. The diagnostic performances of these models were compared. By utilizing the pretrained ResNet50V2 with fine-tuning and gradual unfreezing, we achieved a 5-fold average validation accuracy of 0.920. The diagnostic performance on the testing set demonstrated an accuracy of 89.0%, a sensitivity of 81.8%, a specificity of 91.6%, a positive predictive value of 78.3%, and a negative predictive value of 93.2%. This performance surpasses that of other models in our study. The corresponding Grad-CAM visualizations were also presented to provide explanations for the diagnosis. This study presents an effective and objective ultrasound method for distinguishing between malignant and benign SGTs, which could assist in preoperative evaluation.

Imaging of Major Salivary Gland Lesions and Disease

Infectious and inflammatory disorders are the commonest pathologies to affect the major salivary glands however frequently overlap in clinical presentation. Imaging plays an important role in diagnosis, usually initially performed by CT or ultrasound. MRI, with its superior soft-tissue characterization compared with CT, provides a better evaluation of tumors and tumor-like conditions. Imaging features may suggest that a mass is more likely to be benign versus malignant, however, biopsy is often needed to establish a definitive histopathologic diagnosis. Imaging plays a key role in the staging of neoplastic disease.

Surgery for Cystadenoma of the Retromolar Pad Area With Reconstruction Using a Buccal Fat Pad Flap: A Case Report

Salivary gland tumors can also occur rarely in the retromolar area, though common near the junction of hard and soft palate, labial mucosa, and buccal mucosa. Most salivary gland tumors in the retromolar pad area are malignant and should be excised. The cystadenoma is a rare, benign, salivary gland tumor. Importantly, incomplete resection of this tumor can lead to recurrence or cervical lymph node metastasis. We reported herein a case of cystadenoma arising in the right retromolar pad area in a 63-year-old male patient who underwent reconstruction using a buccal fat pad flap (BFPF) after the surgical removal of the tumor with a 10-mm margin left a defect with bone exposure. No evidence of recurrence or complication was found at the postoperative, three-year follow-up.

Comparison of Different Machine Models Based on Multi-Phase Computed Tomography Radiomic Analysis to Differentiate Parotid Basal Cell Adenoma From Pleomorphic Adenoma

Objective

This study explored the value of different radiomic models based on multiphase computed tomography in differentiating parotid pleomorphic adenoma (PA) and basal cell tumor (BCA) concerning the predominant phase and the optimal radiomic model.

Methods

This study enrolled 173 patients with pathologically confirmed parotid tumors (training cohort: n=121; testing cohort: n=52). Radiomic features were extracted from the nonenhanced, arterial, venous, and delayed phases CT images. After dimensionality reduction and screening, logistic regression (LR), K-nearest neighbor (KNN) and support vector machine (SVM) were applied to develop radiomic models. The optimal radiomic model was selected by using ROC curve analysis. Univariate and multivariable logistic regression was performed to analyze clinical-radiological characteristics and to identify variables for developing a clinical model. A combined model was constructed by integrating clinical and radiomic features. Model performances were assessed by ROC curve analysis.

Results

A total of 1036 radiomic features were extracted from each phase of CT images. Sixteen radiomic features were considered valuable by dimensionality reduction and screening. Among radiomic models, the SVM model of the arterial and delayed phases showed superior predictive efficiency and robustness (AUC, training cohort: 0.822, 0.838; testing cohort: 0.752, 0.751). The discriminatory capability of the combined model was the best (AUC, training cohort: 0.885; testing cohort: 0.834).

Conclusions

The diagnostic performance of the arterial and delayed phases contributed more than other phases. However, the combined model demonstrated excellent ability to distinguish BCA from PA, which may provide a non-invasive and efficient method for clinical decision-making.

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.

CT-based radiomics analysis of different machine learning models for differentiating benign and malignant parotid tumors

OBJECTIVES

This study aimed to explore and validate the value of different radiomics models for differentiating benign and malignant parotid tumors preoperatively.

METHODS

This study enrolled 388 patients with pathologically confirmed parotid tumors (training cohort: n = 272; test cohort: n = 116). Radiomics features were extracted from CT images of the non-enhanced, arterial, and venous phases. After dimensionality reduction and selection, radiomics models were constructed by logistic regression (LR), support vector machine (SVM), and random forest (RF). The best radiomic model was selected by using ROC curve analysis. Univariate and multivariable logistic regression was applied to analyze clinical-radiological characteristics and identify variables for developing a clinical model. A combined model was constructed by incorporating radiomics and clinical features. Model performances were assessed by ROC curve analysis, and decision curve analysis (DCA) was used to estimate the models' clinical values.

RESULTS

In total, 2874 radiomic features were extracted from CT images. Ten radiomics features were deemed valuable by dimensionality reduction and selection. Among radiomics models, the SVM model showed greater predictive efficiency and robustness, with AUCs of 0.844 in the training cohort; and 0.840 in the test cohort. Ultimate clinical features constructed a clinical model. The discriminatory capability of the combined model was the best (AUC, training cohort: 0.904; test cohort: 0.854). Combined model DCA revealed optimal clinical efficacy.

CONCLUSIONS

The combined model incorporating radiomics and clinical features exhibited excellent ability to distinguish benign and malignant parotid tumors, which may provide a noninvasive and efficient method for clinical decision making.

KEY POINTS

The current study is the first to compare the value of different radiomics models (LR, SVM, and RF) for preoperative differentiation of benign and malignant parotid tumors. A CT-based combined model, integrating clinical-radiological and radiomics features, is conducive to distinguishing benign and malignant parotid tumors, thereby improving diagnostic performance and aiding treatment.

Management of malignant submandibular gland tumors: A 30-year experience from a single center

OBJECTIVE

Owing to histologic heterogeneity, biological behavior, and rarity, recommendations for the treatment of malignant submandibular gland tumors (MSGT) are inconsistent. The aim of this study was to present a single-center experience in the treatment of MSGT with an emphasis on surgical treatment, including indication on elective neck dissection (END).

STUDY DESIGN

Twenty-four MSGT were primary surgically treated (gland excision with neck dissection). Their records were retrospectively collected and analyzed.

RESULTS

The most frequent histology was adenoid cystic carcinoma (41.6%), followed by mucoepidermoid carcinoma (25%) and carcinoma ex pleomorphic adenoma (16.7%). There were 18 elective and 6 therapeutic neck dissections. Histopathologic examination confirmed 29% (7/24) of positive neck dissection specimens. The Kaplan-Meier analysis presented rates of disease-specific survival, disease-free survival, and overall survival (OS) of 81%, 78%, and 52% at 5 years, respectively. Patients undergoing postoperative radiotherapy had significantly higher OS rates compared with patients treated with surgery alone (P = .0209).

CONCLUSION

Results of this study suggest that END has questionable benefit in early stage MSGT. Elective selective neck dissection levels I-III is recommended in high-grade and advanced stage MSGT without evidence of multilevel lymphadenopathy.

Tracking of Oral and Craniofacial Stem Cells in Tissue Development, Regeneration, and Diseases

PURPOSE OF REVIEW

The craniofacial region hosts a variety of stem cells, all isolated from different sources of bone and cartilage. However, despite scientific advancements, their role in tissue development and regeneration is not entirely understood. The goal of this review is to discuss recent advances in stem cell tracking methods and how these can be advantageously used to understand oro-facial tissue development and regeneration.

RECENT FINDINGS

Stem cell tracking methods have gained importance in recent times, mainly with the introduction of several molecular imaging techniques, like optical imaging, computed tomography, magnetic resonance imaging, and ultrasound. Labelling of stem cells, assisted by these imaging techniques, has proven to be useful in establishing stem cell lineage for regenerative therapy of the oro-facial tissue complex. Novel labelling methods complementing imaging techniques have been pivotal in understanding craniofacial tissue development and regeneration. These stem cell tracking methods have the potential to facilitate the development of innovative cell-based therapies.

Extracapsular Dissection for Small Benign Tumors of Parotid Gland: A Case Report on Contemporary Technique

Salivary gland tumor looms as painless enlarging mass which may embrace in both major or minor glands. Pleomorphic adenoma (PA) accord about 40-70% of all salivary gland tumors, where Warthin tumor, basal cell adenoma (BCA), adenoid cystic carcinoma (ACC), and sebaceous tumors have a strong predilection for major salivary gland. However, polymorphous low-grade adenocarcinoma (PLGA) has a marked predilection for the minor salivary gland. We present a case of PA in a 26-year-old male patient that has been successfully managed by extracapsular dissection (ECD) without any post-operative complications.

Patterns of care analysis for salivary gland cancer: a survey within the German Society of Radiation Oncology (DEGRO) and recommendations for daily practice

Background

Salivary gland cancer (SGC) is rare and a heterogeneous type of cancer. Prospective randomized trials are lacking. No guideline focusing on standard procedures of radiotherapy (RT) in the treatment of SGC exists. Therefore, we surveyed the members of the German Society of Radiation Oncology (DEGRO) to gain information about current therapeutic strategies of SGC.

Methods

An anonymous questionnaire was designed and made available on the online platform umfrageonline.com. The corresponding link was sent to all DEGRO members who provided their user data for contact purposes. Alternatively, a PDF printout version was sent. Frequency distributions of responses for each question were calculated. The data were also analyzed by type of institution.

Results

Sixty-seven responses were received, including answers from 21 university departments, 22 non-university institutions, and 24 radiation oncology practices. Six participants reported that their departments (practice: n = 5, non-university hospital: n = 1) did not treat SGC, and therefore the questionnaire was not completed. Concerning radiation techniques, target volume definition, and concomitant chemotherapy, treatment strategies varied greatly among the participants. Comparing university vs. non-university institutions, university hospitals treat significantly more patients with SGC per year and initiated more molecular pathological diagnostics.

Conclusion

SGC represents a major challenge for clinicians, as reflected by the inhomogeneous survey results regarding diagnostics, RT approaches, and systemic therapy. Future prospective, multicenter clinical trials are warranted to improve and homogenize treatment of SGC and to individualize treatment according to histologic subtypes and risk factors.

Supplementary Information

The online version of this article (10.1007/s00066-021-01833-x) contains supplementary material, which is available to authorized users.

An Overview on the Histogenesis and Morphogenesis of Salivary Gland Neoplasms and Evolving Diagnostic Approaches

Simple Summary

Diagnosing salivary gland neoplasms (SGN) remain a challenge, given their underlying biological nature and overlapping features. Evolving techniques in molecular pathology have uncovered genetic mutations resulting in these tumors. This review delves into the molecular etiopatho-genesis of SGN, highlighting advanced diagnostic protocols that may facilitate the identification and therapy of a variety of SGN.

Abstract

Salivary gland neoplasms (SGN) remain a diagnostic dilemma due to their heterogenic complex behavior. Their diverse histomorphological appearance is attributed to the underlying cellular mechanisms and differentiation into various histopathological subtypes with overlapping fea-tures. Diagnostic tools such as fine needle aspiration biopsy, computerized tomography, magnetic resonance imaging, and positron emission tomography help evaluate the structure and assess the staging of SGN. Advances in molecular pathology have uncovered genetic patterns and oncogenes by immunohistochemistry, fluorescent in situ hybridization, and next–generation sequencing, that may potentially contribute to innovating diagnostic approaches in identifying various SGN. Surgical resection is the principal treatment for most SGN. Other modalities such as radiotherapy, chemotherapy, targeted therapy (agents like tyrosine kinase inhibitors, monoclonal antibodies, and proteasome inhibitors), and potential hormone therapy may be applied, depending on the clinical behaviors, histopathologic grading, tumor stage and location, and the extent of tissue invasion. This review delves into the molecular pathways of salivary gland tumorigenesis, highlighting recent diagnostic protocols that may facilitate the identification and management of SGN.

The Clinical Characteristics and CT Findings of Parotid and Submandibular Gland Tumours

Objective

To investigate the clinical characteristics and CT findings of parotid and submandibular gland tumours. Materials and methods. From May 2017 to April 2020, all patients with clinically proven parotid and submandibular gland enlargement and palpable masses underwent CT examinations. All patients were confirmed by pathology after surgery. The clinical characteristics and CT features were observed and evaluated. The mean density values before and after enhancement were measured and analyzed. The chi-square test, one-way ANOVA, and Student's t-test were used.

Results

Ninety-four patients with a total of 94 unilateral tumours in the parotid and submandibular glands were enrolled, including 38 pleomorphic adenomas (PAs), 27 Warthin's tumours (WTs), and 29 malignant tumours (MTs). The majority of the PAs (28/38) and MTs (23/29) were located in the parotid gland; the others were located in the submandibular gland. All the WTs were in the parotid gland. The most common benign tumours of the parotid gland were PAs (28/38, 73.7%) and WTs (27/27, 100%), and the most common MTs were mucoepidermoid carcinoma, acinic cell carcinoma, and squamous cell carcinoma (4/29, 13.8%). The most common benign and malignant tumours in the submandibular gland were PAs (10/38, 26.3%) and ductal adenocarcinomas (3/4, 75%). The majority of PA patients (28/38) were female, compared with WT (2/27) (P < 0.001) and malignant tumour patients (10/29) (P < 0.01). A significant difference was also found between WTs and MTs in female patients (P < 0.05). The mean age of PA patients was 43.4 ± 12.1 years, which was lower than that of WTs (62.1 ± 11.7) and MTs (58 ± 14.18) (P < 0.001, P < 0.001, and P=0.244, respectively). On CT imaging, the mean diameter of the PAs and WTs was significantly smaller than that of the MTs (P=0.001 and P < 0.001), and no difference was observed between the PAs and WTs (P=0.275). In the parotid gland, the superficial lobe was more frequently involved than the deep lobe (PAs, 22 : 6; WTs, 17 : 10; and MTs, 15 : 8). The majority of PAs and WTs demonstrated round shapes (25/38, 19/27) and were well defined (30/38, 24/27); by contrast, most MTs were lobulated, irregular shapes (24/29), and ill defined (25/29). On plain CT, the PAs were usually homogeneous, while MTs were frequently heterogeneous, with more necrosis, larger cystic areas, and more haemorrhage or calcification. The mean CT values of PAs, WTs, and MTs were 39.2 ± 3.9 HU, 39.1 ± 3.0 HU, and 37.6 ± 3.1 HU (P > 0.05), respectively. On contrast CT, the WTs were significantly enhanced compared with MTs and PAs, with mean CT values of 53.5 ± 4.0 HU, 84.4 ± 6.0 HU, and 65.2 ± 3.8 HU, respectively (all P < 0.001). The mean CT value changes for PAs, WTs, and MTs (∆) were 14.4 ± 3.0 HU, 45.3 ± 4.5 HU, and 27.7 ± 2.5 HU, respectively. Significant differences were observed between ∆_PAs and ∆_WTs, ∆_PAs and ∆_MTs, and ∆_WTs and ∆_MTs (all P < 0.001).

Conclusion

Parotid and submandibular gland tumours have some typical clinical characteristics and CT findings, and plain and early contrast-phase CT combined with clinical parameters may be helpful for diagnosis.

Management of Salivary Gland Malignancy: ASCO Guideline

PURPOSE

To provide evidence-based recommendations for practicing physicians and other healthcare providers on the management of salivary gland malignancy.

METHODS

ASCO convened an Expert Panel of medical oncology, surgical oncology, radiation oncology, neuroradiology, pathology, and patient advocacy experts to conduct a literature search, which included systematic reviews, meta-analyses, randomized controlled trials, and prospective and retrospective comparative observational studies published from 2000 through 2020. Outcomes of interest included survival, diagnostic accuracy, disease recurrence, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.

RESULTS

The literature search identified 293 relevant studies to inform the evidence base for this guideline. Six main clinical questions were addressed, which included subquestions on preoperative evaluations, surgical diagnostic and therapeutic procedures, appropriate radiotherapy techniques, the role of systemic therapy, and follow-up evaluations.

RECOMMENDATIONS

When possible, evidence-based recommendations were developed to address the diagnosis and appropriate preoperative evaluations for patients with a salivary gland malignancy, therapeutic procedures, and appropriate treatment options in various salivary gland histologies.Additional information is available at www.asco.org/head-neck-cancer-guidelines.

Radiomics-based comparison of MRI and CT for differentiating pleomorphic adenomas and Warthin tumors of the parotid gland: a retrospective study

OBJECTIVE

The objective of this study was to compare the diagnostic performance of magnetic resonance imaging (MRI) and computed tomography (CT) in differentiating pleomorphic adenomas from Warthin tumors using radiomics.

STUDY DESIGN

We retrospectively reviewed 626 patients who underwent preoperative MRI or CT for parotid tumor diagnosis. Patient groups were balanced by propensity score matching (PSM) and 123 radiomic features were extracted from tumor images. Radiomic signatures (rad-scores) were generated using a least absolute shrinkage and selection operator logistic regression model. The Canny edge detector was used to define tumor borders (border index). The diagnostic performance of rad-score and border index before and after PSM was evaluated with area under the receiver operating characteristic curve analysis.

RESULTS

For differentiation of pleomorphic adenomas and Warthin tumors, rad-score and border index areas under the curve for MRI after PSM were 0.911 (95% confidence interval [CI], 0.871-0.951) and 0.716 (95% CI, 0.646-0.787), respectively; those for CT were 0.876 (95% CI, 0.829-0.923) and 0.608 (95% CI, 0.527-0.690), respectively. Tumor border index on MRI, but not CT, had superior diagnostic performance (P < .05); MRI- and CT-based rad-scores showed similar performance (P >.05).

CONCLUSIONS

MRI is superior to CT for tumor margin examination; however, the radiomics features of both modalities showed no difference.

Cross-sectional imaging and cytologic investigations in the preoperative diagnosis of parotid gland tumors - An updated literature review

An accurate preoperative diagnosis of parotid tumors is essential for the selection and planning of surgical treatment. Various modern cross-sectional imaging and cytologic investigations can support the differential diagnosis of parotid tumors. The aim of this study was to achieve a comprehensive and updated review of modern imaging and cytologic investigations used in parotid tumor diagnosis, based on the latest literature data. This literature review could serve as a guide for clinicians in selecting different types of investigations for the preoperative differential diagnosis of parotid tumors. Magnetic resonance imaging (MRI) with its dynamic and advanced sequences is the first-line imaging investigation used in differentiating parotid tumors. Computed tomography (CT) and positron emission tomography (PET)-CT provide limited indications in differentiating parotid tumors. Fine needle aspiration biopsy and core needle biopsy can contribute with satisfactory results to the cytological diagnosis of parotid tumors. Dynamic MRI with its dynamic contrast-enhanced and diffusion-weighted sequences provides the best accuracy for the preoperative differential diagnosis of parotid tumors. CT allows the best evaluation of bone invasion, being useful when MRI cannot be performed, and PET-CT has value in the follow-up of cancer patients. The dual cytological and imaging approach is the safest method for an accurate differential diagnosis of parotid tumors.

Narrative review of multiparametric ultrasound in parotid gland evaluation

Disorders affecting parotid gland represent a heterogeneous group comprising congenital, inflammatory and neoplastic diseases which show a focal or diffuse pattern of appearance. The differentiation of neoplastic from non-neoplastic conditions of parotid glands is pivotal for the diagnostic imaging. Frequently there is evidence of overlapping between the clinical and the imaging appearance of the various pathologies. The parotid gland is also often object of study with the combination of different techniques [ultrasound-computed tomography-magnetic resonance imaging (US-CT-MRI), ex.]. Compared to other dominant methods of medical imaging, US has several advantages providing images in real-time at lower cost, and without harmful use of ionizing radiation and of contrast enhancement. B-mode US, and the microvascular pattern color Doppler are usually used as first step evaluation of parotid lesions. Elastography and contrast-enhanced US (CEUS) has opened further possible perspectives to improve the differentiation between benign and malignant parotid lesions. The characterization of the parotid tumors plays a crucial role for their treatment planning and for the prediction of possible surgical complications. We present, here an updated review of the most recurrent pathologies of parotid gland focusing on the diagnostic power of multiparametric US including CEUS and ultrasound elastography (USE); limitations, advantages and the main key-points will be presented.

Salivary duct carcinoma: Updates in histology, cytology, molecular biology, and treatment

Salivary duct carcinoma (SDC) is an aggressive subtype of primary salivary gland carcinoma, often with an advanced stage at presentation and high rates of metastasis and recurrence. It most commonly arises in the parotid gland of older men and microscopically resembles high-grade breast ductal carcinoma. While 50 years have lapsed since the first report of this entity, recent intensive studies have shed light on its biologic, genetic, and clinical characteristics. The diagnosis of SDC is aided by the immunohistochemical expression of androgen receptor (AR) coupled with its characteristic histomorphology. Fine-needle aspiration typically reveals cytologic features of high-grade carcinoma, and ancillary studies using cell block material can facilitate the specific diagnosis of SDC. In surgical specimens, certain histologic features are important prognostic factors, including nuclear pleomorphism, mitotic counts, vascular invasion, and the morphology at the invasion front. Several clinical studies have shown promising results using targeted therapy for AR and human epidermal growth factor receptor 2 (HER2), and the latest version of the National Comprehensive Cancer Network guidelines recommends the evaluation of AR and HER2 status before treatment. Recent molecular analyses have revealed multiple heterogeneous alterations in well-known oncogenes and tumor suppressor genes, including TP53, HRAS, PIK3CA, PTEN, and BRAF. Clinical trials of drugs targeting these genes may broaden the treatment options for SDC in the near future.

Multiparametric magnetic resonance imaging of parotid tumors: A systematic review

PURPOSE

The purpose of this systematic review was to provide an overview of the contribution of multiparametric magnetic resonance imaging (MRI) in the diagnosis of parotid tumors (PT) and recommendations based on current evidences.

MATERIAL AND METHODS

We performed a retrospective systematic search of PubMed, EMBASE, and Cochrane Library databases from inception to January 2020, using the keywords "magnetic resonance imaging" and "salivary gland neoplasms".

RESULTS

The initial search returned 2345 references and 90 were deemed relevant for this study. A total of 54 studies (60%) reported the use of diffusion-weighted imaging (DWI) and 28 studies (31%) the use of dynamic contrast-enhanced (DCE) imaging. Specific morphologic signs of frequent benign PT and suggestive signs of malignancy on conventional sequences were reported in 37 studies (41%). DWI showed significant differences in apparent diffusion coefficient (ADC) values between benign and malignant PT, and especially between pleomorphic adenomas and malignant PT, with cut-off ADC values between 1.267×10^-3mm²/s and 1.60×10^-3mm²/s. Perfusion curves obtained with DCE imaging allowed differentiating among pleomorphic adenomas, Warthin's tumors, malignant PT and cystic lesions. The combination of morphological MRI sequences, DCE imaging and DWI helped increase the diagnostic accuracy of MRI.

CONCLUSION

Multiparametric MRI, including morphological MRI sequences, DWI and DCE imaging, is the imaging modality of choice for the characterization of focal PT and provides features that are highly suggestive of a specific diagnosis.

Multiparametric ultrasound evaluation of parotid gland tumors: B-mode and color Doppler in comparison and in combination with contrast-enhanced ultrasound and elastography. A case report of a misleading diagnosis

Preoperative characterization of parotid gland tumors using imaging or cytological examination (fine-needle aspiration cytology) has a strong clinical and therapeutic impact, but it is often difficult due to the tumors' histological heterogeneity. The recent introduction of contrast-enhanced ultrasound (CEUS) and elastography, in the context of multiparametric ultrasound evaluation, contributed to improving the preoperative diagnosis of many diseases affecting the liver, breast, and thyroid, as well as other organs. However, limited evidence is available on the use and the diagnostic power of these techniques in parotid gland neoplasms. In this paper, we present a case of a parotid lesion that highlights the importance of a complete workup using multiparametric ultrasound evaluation, including CEUS and elastography, to identify malignant tumors of the parotid gland.

The diagnostic value of cytology in parotid Warthin's tumors: international multicenter series

INTRODUCTION

Warthin's tumor (WT) is a common benign salivary gland neoplasm with a negligible risk of malignant transformation. However, there is a risk of malignant tumors being misdiagnosed as WT on cytology and inappropriately managed conservatively.

METHODS

Patients from nine centers in Italy and the United Kingdom undergoing parotid surgery for cytologically diagnosed WT were included in this multicenter retrospective series. Definitive histology was compared with preoperative cytological diagnoses. Surgical complications were recorded.

RESULTS

A total of 496 tumors were identified. In 88.9%, the final histological diagnosis was WT. In 21 cases (4.2%) a malignant neoplasm was diagnosed, which had been incorrectly labeled as WT on cytology.

CONCLUSIONS

The risk of undiagnosed malignancy should be balanced against surgical risks when considering the management of WT. Although nonsurgical management remains an appropriate option, there may be a rationale for serial clinical or radiological evaluation if surgical excision is not performed.

Nonmicrosurgical Grafting for Facial Nerve Branches with Permanent Sensational Functional Outcome

A 49-year-old man underwent intraoperatively modified procedure from superficial to radical parotidectomy with excision of the facial nerve 4 branches, temporal, zygomatic, buccal, and mandibular. We have dissected and harvested the branches of the great auricular nerve to repair the defects of the temporal, zygomatic, buccal, and mandibular nerves without microsurgery aid. The aims of the repair were just to mark the nerve endings, to try autologous grafting, and to avoid neuroma(s) formation, although neuroma(s) formations from motor nerves are rare. We did an immediate temporary nonmicrosurgical nerve grafting, and we have sutured each nerve anastomosis by 2-3 stitches of Prolene 6-0. We have observed facial nerve branches' recovery on the second month, even with radiation therapy, and then gradually more improvements on the third month and then on the sixth month of the follow-up. Finally, the procedure results in permanent sensational functional outcome after 1 year. Because we did not plan a microsurgical repair, this case report does not support any intended nonmicrosurgical procedures for facial nerve repair, but it raises questions for laboratory and animal investigations about the size of Prolene we have used, grip repair taking the epineurium and fascicle in mass closure, and the positive fast functional results. In surgical environments where microscope or microinstruments are lacking, one can still perform primary nerve grafting.

AHNS series: Do you know your guidelines? Diagnosis and management of salivary gland tumors

This article is the next installment of the series "Do you know your guidelines" presented by the Education Committee of the American Head and Neck Society. Guidelines for the workup and management of tumors of the major and minor salivary glands are reviewed.

Coincidence of Malignant Melanoma and an Incidently Discovered Parotid Mass Presenting a Diagnostic Challenge

Parotid masses coincided with skin tumors in head and neck region may represent a serious diagnostic challenge. Conventional imaging modalities such as computed tomography, magnetic resonance imaging may help to determine nature of the masses. Positron emission tomography - computed tomography imaging is reported to be useful for the detection of malignancy in the parotid gland. But in some situations all of them become insufficient. We present a case of cheek malignant melanoma with an incidentally discovered parotid mass during the investigation. We describe the problems experienced in the course of differential diagnosis and decision making in terms of surgical management. As a result, the most reliable diagnosis of suspicious parotid lesions accompanying head and neck melanomas comes from frozen section analyses. The other diagnostic tools are not reliable enough to allow a safe surgical plan in terms of regional treatment; however, the significance of positron emission tomography - computed tomography in distant metastasis investigation should always be kept in mind.

Surgeon-performed ultrasound for the assessment of parotid masses

BACKGROUND

Studies on parotid gland ultrasound assessments performed specifically by surgeons are seldom reported.

METHODS

Retrospective series of a single academic surgeon experience, analyzing 70 new parotid masses with evaluable preoperative SP-US characteristics, location measurements, and perioperative events.

RESULTS

31/70 masses were malignant. SP-US characteristics significantly associated with both malignancy and positive margins included extraparenchymal extension, irregular borders, hypervascularity, infiltration, and the lack of deep enhancement. The larger the skin-to-deep-aspect-of-tumor distance, the more likely the tumor was deep to FN. For the 39 cytologically benign tumors, neither CT nor MRI provided additional information to change management except for full delineation of parapharyngeal space extension in 2 cases.

CONCLUSION

SP-US can help predict parotid mass benignity/malignancy, positive margin risk, and tumor relation to FN. SP-US may be used as the sole imaging in cytologically benign tumors unless the deep tumor extent cannot be identified.

Cross-sectional Imaging of Parotid Gland Nodules: A Brief Practical Guide

Clinical evaluation and ultrasound examination are the first steps in the evaluation of a patient with a swelling of the parotid region. After the detection of a nodular lesion, cytological or histological confirmation is usually performed to achieve the diagnosis, while the choice of cross-sectional imaging (computed tomography scan and magnetic resonance imaging) may significantly vary from one physician to another, on the basis of the degree of confidence that both radiologist and surgeon have with this kind of imaging. This work focuses on some essential “reporting points” in cross-sectional imaging evaluation of parotid nodules, chiefly helpful to the radiologist when the ultrasonography assessment is considered incomplete and requires a further evaluation.

Sclerosing mucoepidermoid carcinoma of the sublingual gland

INTRODUCTION

Sclerosing mucoepidermoid carcinoma of the salivary gland is a rare subtype of mucoepidermoid carcinoma. The most common site of sclerosing mucoepidermoid carcinoma of the salivary glands is the parotid gland, followed by the submandibular gland, and the minor salivary glands.

OBSERVATION

Here we report the first case of sclerosing mucoepidermoid carcinoma of the sublingual gland.

DISCUSSION

Clinicians should consider sclerosing mucoepidermoid carcinoma in the differential diagnosis of salivary gland neoplasm. Surgical excision with clear margins seems to be a sufficient initial treatment option for sclerosing mucoepidermoid carcinoma of the salivary gland.

Review on the applications of ultrasonography in dentomaxillofacial region

Use of ultrasonography (US) in dentomaxillofacial region became popular in recent years owing to increasing radiation dose concerns and economic limitations. It helps to visualize fine detail of the surface structure of the oral and maxillofacial tissues without ionizing radiation. In diagnostic ultrasound, high frequency sound waves are transmitted into the body by a transducer and echoes from tissue interface are detected and displayed on a screen. Sound waves are emitted via piezoelectric crystals from the ultrasound transducer. US technique can be used in dentomaxillofacial region for the examination of bone and superficial soft tissue, detection of major salivary gland lesions, temporomandibular joint imaging, assessment of fractures and vascular lesions, lymph node examination, measurement of the thickness of muscles and visualization of vessels of the neck. It has the potential to be used in the evaluation of periapical lesions and follow up of periapical bone healing. Also, it may be used for the evaluation of periodontal pocket depth and for the determination of gingival thickness before dental implantology.