Molecular Aspects of Mucoepidermoid Carcinoma and Adenoid Cystic Carcinoma of the Salivary Gland

BACKGROUND

Salivary gland tumors (SGTs) are rare and highly heterogeneous lesions, making diagnosis a challenging activity. In addition, the small number of studies and samples evaluated difficults the determination of prognosis and diagnosis. Despite the solid advances achieved by research, there is still an intense need to investigate biomarkers for diagnosis, prognosis and that explain the evolution and progression of SGTs.

METHODS

We performed a comprehensive literature review of the molecular alterations focusing on the most frequent malignant SGTs: mucoepidermoid carcinoma and adenoid cystic carcinoma.

RESULTS

Due to the importance of biomarkers in the tumorigenenic process, this review aimed to address the mechanisms involved and to describe molecular and biomarker pathways to better understand some aspects of the pathophysiology of salivary gland tumorigenesis.

CONCLUSIONS

Molecular analysis is essential not only to improve the diagnosis and prognosis of the tumors but also to identify novel driver pathways in the precision medicine scenario.

Clinicopathological features and prognostic factors of salivary gland myoepithelial carcinoma: institutional experience of 42 cases

Myoepithelial carcinoma (MECA) is a rare type of carcinoma for which the clinicopathological features and prognostic factors have not yet been fully clarified. A retrospective study of 42 patients diagnosed with salivary gland MECA was performed, focusing on the clinicopathological features and prognostic factors. Of the 42 patients, 20 died of cancer, 20 lived without tumour, one lived with distant metastasis, and one was lost to follow-up. Overall, 69.0% had tumour recurrence, 16.7% had cervical nodal metastasis, and 21.4% had distant metastasis. The 5-year overall survival rate was 70.2%. Kaplan-Meier analysis revealed that patients with pathological positive lymph nodes (pN+), multiple recurrences of tumour, and higher histological grade had worse overall survival. Multivariate Cox analysis indicated pN+ and higher histological grade to be independent predictors of decreased survival. The 5-year overall survival rate in the pN0 group was 87.5%, while that in the pN+ group was 28.6%. In conclusion, myoepithelial carcinoma can be defined as a tumour with a high incidence of recurrence and poor prognosis, especially in pN+ patients. Pathological positive lymph nodes and histological grade may serve as predictors of survival.

Dynamic Role of miRNAs in Salivary Gland Carcinomas: From Biomarkers to Therapeutic Targets

BACKGROUND

Salivary gland carcinomas (SGCs) are a rare group of malignant neoplasms of the head and neck region. MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been associated with the control biological process and oncogenic mechanism by the regulation of gene expression at the post-transcriptional level. Recent evidence has suggested that miRNA expression may play a role in the tumorigenesis and carcinogenesis process in SGCs.

METHODS

This review provides a comprehensive literature review of the role of miRNAs expression in SGCs focusing on the diagnostic, prognostic, and therapeutic applications.

RESULTS

In this review, numerous dysregulated miRNAs have demonstrated an oncogenic and suppressor role in SGCs.

CONCLUSION

In the future, these miRNAs may eventually constitute useful diagnostic and prognostic biomarkers that may lead to a better understanding of SGCs oncogenesis. Additionally, the development of therapeutic agents based on miRNAs may be a promising target in SGC treatment.

Expression of FOXI1 and POU2F3 varies among different salivary gland neoplasms and is higher in Warthin tumor

PURPOSE

Salivary gland tumors are histologically diverse. Ionocytes and tuft cells, rare epithelial cells found in normal salivary glands, might be associated with salivary tumors. Here, we explored the expression of FOXI1 and POU2F3, master regulators of ionocytes and tuft cells, respectively, for common salivary neoplasms using immunohistochemistry.

METHODS

We analyzed normal salivary tissues and nine salivary gland tumors; Warthin tumors (WT), pleomorphic adenomas (PA), basal cell adenomas, and oncocytomas were benign, whereas mucoepidermoid, adenoid cystic, acinic cell, salivary duct carcinomas, and polymorphous adenocarcinomas were malignant.

RESULTS

Normal salivary glands contained a few FOXI1- and POU2F3-positive cells in the ducts instead of the acini, consistent with ionocytes and tuft cells, respectively. Among the benign tumors, only WTs and PAs consistently expressed FOXI1 (10/10 and 9/10, respectively). The median H-score of WTs was significantly higher than that of PAs (17.5 vs. 4, P = 0.01). While WTs and PAs harbored POU2F3-positive cells (10/10 and 9/10, respectively), the median H-score was higher in WTs than in PAs (10.5 vs 4, respectively). Furthermore, WTs exhibited a unique staining pattern of FOXI1- and POU2F3-positive cells, which were present in luminal and abluminal locations, respectively. Whereas none of the malignant tumors expressed FOXI1, only adenoid cystic carcinoma consistently expressed POU2F3 (5/5), with a median H-score of 4.

CONCLUSION

The expression patterns of the characteristic transcription factors found in ionocytes and tuft cells vary among salivary gland tumor types and are higher in WT, which might be relevant for understanding and diagnosing salivary gland neoplasms.

Pleomorphic adenoma of the nasal septum: A case report

INTRODUCTION

Pleomorphic adenomas are benign salivary gland tumors with epithelial, myxoid, and mucoid components. They rarely occur in the upper respiratory tract where the predominant site is the nasal septum, leading to symptoms of nasal obstruction. Identifying these tumors requires histopathological examination, and they are usually managed surgically.

PRESENTATION OF CASE

A middle-aged lady presented to the outpatient otorhinolaryngology clinic with symptoms of unilateral nasal obstruction. Nasal endoscopy in the clinic revealed a right-sided anterior nasal septal vascular mass, which was confirmed with a contrast-enhanced CT scan with suspicion of septal hemangioma. Surgical examination and endoscopic removal of the septal mass were carried out under anesthesia, and histopathology of the specimen showed predominant myoepithelial cellularity with scanty stroma, consistent with a diagnosis of pleomorphic adenoma. The patient had an uneventful post-operative stay and follow-up with no recurrence.

DISCUSSION

Nasal cavity pleomorphic adenomas are important to identify and treat, as they can recur and potentially turn malignant. Endoscopic endonasal surgery is emerging as the treatment of choice for these adenomas, as it is associated with minimal morbidity and cosmetic impact.

CONCLUSION

We report a rare case of nasal septal pleomorphic adenoma in a middle-aged female, which was successfully treated with endoscopic endonasal surgery.

BubR1 and cyclin B1 immunoexpression in pleomorphic adenoma and polymorphous adenocarcinoma of minor salivary glands

The immunoexpression of BubR1 and cyclin B1 in pleomorphic adenoma (PA) and polymorphic adenocarcinoma (PAC) in minor salivary glands is poorly studied. Thus, a retrospective and observational study was performed to provide a better understanding of the role and immunopositivity patterns of these proteins in these lesions. Sixteen cases of PA and 16 cases of PAC were selected. Parenchyma cells were submitted to quantitative immunohistochemical analysis through the labeling index. Cytoplasmic immunoexpression of BubR1 was observed in neoplastic cells from all analyzed PA and PAC cases. All PA cases and 93.7% of PAC exhibited nuclear immunoexpression of BubR1. Higher cytoplasmic and nuclear immunoexpression of BubR1 was observed in PAC (p = 0.001 and p = 0.122, respectively). Cytoplasmic immunoexpression of cyclin B1 was observed in all cases of PA and PAC, with a higher labeling index in the latter (p < 0.001). There was a significant positive correlation between nuclear and cytoplasmic BubR1 immunoexpressions (p < 0.001) in PA and a significant negative correlation between BubR1 and cyclin B1 cytoplasmic immunoexpressions (p = 0.014) in PAC. The higher cytoplasmic and nuclear immunoexpression of BubR1 in PACs suggests the continuous maintenance of neoplastic cells in the cell cycle and migration. Higher immunoexpression of cyclin B1 supports this lesion's enhanced proliferative and migration ability.

Influence of p16 Protein Immunostaining on Histopathological Features of Pleomorphic Adenoma and Carcinoma ex- Pleomorphic Adenoma

The objective of this study was to evaluate the role of p16 in histologic characteristics and transition of Pleomorphic Adenoma (PA) to Carcinoma ex-PA (CxPA). So, 60 PA and 4 CxPA were histologic reviewed based on microscopic characteristics proposed by Hellquist, Triantafyllou and Dulguerov (PA) and Morais, Antony and Toluie (CxPA). Immunostaining for p16 was associated in different parenchyma and stroma of both tumors and Fisher's/chi-square tests and Mann-Whitney test were performed (SPSS v20.0, p<0.05). In PA the periductal cells were predominantly p16- and that ductal and myoepithelial cells showed a significant increase in p16+ cells (p<0.001). In CxPA, none of the cases showed p16+ in periductal cells, most parotid cases showed p16+ in ductal cells, and one case of parotid and the submandibular case showed mild immunostaining for myoepithelial cells. There was a small reduction in p16+ in CxPA compared to PA (p=0.537), but in both tumors there was less p16+ cells in solid stroma than other (p<0.001). The p16+ cases of PA had a higher capsular thickness (p=0.047). So, the loss of p16 immunostaining does not seem to be associated with the transition from PA to CxPA, but in both tumors the loss of p16+ cells are related to microscopic aggressiveness.

Clinical features of tumours and tumour-like pathologies involving the buccal fat pad

This study aimed to investigate the clinical, radiological, and pathological characteristics of pathologies involving the buccal fat pad (BFP) and to explore the treatment protocols. The cases of 109 patients with primary pathologies involving the BFP (pBFP) diagnosed between January 2013 and September 2021 were assessed. The patients' clinical presentations and radiological and histopathological findings were analysed retrospectively, and their treatment outcomes were evaluated. The 109 pBFP were categorized as benign tumours (n = 17), malignant tumours (n = 29), vascular malformations (n = 38), and inflammatory masses (n = 25). Of the 17 benign tumours, seven were lipomas, five were pleomorphic adenomas, three were solitary fibrous tumours, and two were other tumours. The 29 malignant tumours included five adenoid cystic carcinomas, six mucoepidermoid carcinomas, three synovial sarcomas, and 15 other tumours. Of the 38 vascular malformations, 37 were venous and one was arteriovenous. Regarding the inflammatory masses, the lesions appeared after cosmetic facial botulinum toxin injection in 13 cases and after other cosmetic facial procedures in five. The upper body of the BFP was the most frequently involved site (79/109), while other frequently involved sites were the lower body (67/109) and the masseteric (41/109), temporal (32/109), and pterygopalatine (30/109) extensions.

Epithelial-myoepithelial carcinoma with multiple recurrences: An unusual presentation

Epithelial-myoepithelial carcinoma (EMC) is a type of malignant salivary gland tumors that is extremely rare. EMC primarily affects major salivary glands, particularly the parotid gland, but minorsalivary glands are also affected. It contributes less than 0.5-1% of all salivary gland neoplasms. Multiple recurrences are relatively rare with EMC. There have been very few reports of multiplerecurrences in the literature. Biphasic tubular structures composed of externalclear cells and inner ductal cells are the distinguishing histopathological feature. However, histological variation is prevalent, making a precise diagnosis challenging. We present a case of EMC that had multiple recurrences during a six-year period.

Salivary gland neoplasms in small biopsies and fine needle aspirations

Salivary gland neoplasms are rare and represent a diverse group of head and neck tumors. Their diagnosis in limited cellularity specimens can be challenging as many of these have overlapping clinical, radiological presentation, and pathologic features. Fine needle aspiration and/or core biopsies are more of a norm than rarity to be performed preoperatively to provide invaluable information that can guide clinical management including surgery. Even though these limited specimens may not always provide a definitive diagnosis; they have high sensitivity in confirming primary neoplasia, assessing the tumor grade, and ruling out non-surgical disease. An algorithmic pattern based approach can help narrow the differential diagnosis; leading to a definitive diagnosis with the help of specific ancillary studies.

Intraoral exophytic lesion in an adolescent: A case report of myoepithelioma with unique clinical presentation

Myoepithelioma is an infrequent benign tumor of the salivary glands, characterized by its composition of myoepithelial cells which can show different shapes and be arranged in various patterns with a well-circumscribed or encapsulated growth. This tumor commonly presents in adults as an asymptomatic swelling of the parotid gland, very rarely in minor salivary glands of children or adolescents, and even rarer in the buccal mucosa, with only six cases reported to date and only one of them presented in an adolescent. We present an additional case of myoepithelioma in the buccal mucosa of a 16-year-old male, with a novel clinical presentation as a non-submucosal exophytic mass. Immunohistochemically, neoplastic cells were positive for CK, S100, p63, and GFAP. The tumour was treated surgically, and the patient showed satisfactory evolution at 1 year of follow-up. The clinical and histopathological characteristics of the reported cases are discussed.

Immunoexpression of Autophagy-Related Proteins in Salivary Gland Tumors: An Exploratory Study

BACKGROUND

Autophagy is a cellular survival mechanism involved in several human diseases, but its participation in the development of salivary gland tumors is not fully understood. This study investigated the immunoexpression of autophagy-related proteins (autophagy-related 7 [Atg7], microtubule-associated protein 1 light chain 3A [LC3A], microtubule-associated protein 1 light chain 3B [LC3B], protein p62 [p62], and phosphorylated mammalian target of rapamycin [p-mTOR]) in pleomorphic adenoma (PA), polymorphous adenocarcinoma (PAC), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (ACC) of salivary glands.

METHODS

Twenty PAs, 20 PACs, 20 MECs, and 14 ACCs were selected. The percentages of cytoplasmic and nuclear positivity for autophagy-related proteins in neoplastic cells were assessed and correlated with histopathological parameters.

RESULTS

Cytoplasmic immunoexpression of Atg7 was observed in all groups, with high median percentages of positivity. Regarding LC3A and LC3B, cytoplasmic immunoexpression was found in most PACs (95%) and in all cases of PA, MEC and ACC, with the highest percentages of positivity in PACs and PAs (p < 0.005). ACCs exhibited lower cytoplasmic immunoexpression of p-mTOR (p < 0.005) and lower nuclear expression of p62 (p < 0.05) when compared to PAs, PACs and MECs. Low nuclear immunoexpression of Atg7, LC3A and p-mTOR and absence of nuclear staining for LC3B were observed in all groups. Regarding histopathological parameters of PAs, MECs and ACCs, there were no significant differences in the expression of autophagy-related proteins. In all groups, positive correlations were observed between the immunoexpression of some autophagy-related proteins (p < 0.05).

CONCLUSIONS

The results suggest the participation of autophagy in the pathogenesis of PA, PAC, MEC, and ACC of salivary glands. Upregulation of autophagy and reduced nuclear translocation of p62 may contribute to the aggressive biological behavior of salivary gland ACC.

Head and neck mucoepidermoid carcinoma: does AFIP histological grading correlate with rate of nodal metastases?

OBJECTIVE

The aim of this study is to retrospectively evaluate the presentation of head and neck mucoepidermoid carcinoma at the Royal Melbourne Hospital and identify the significance of AFIP histological grading on the risk of neck metastasis and cancer free survival.

MATERIALS AND METHODS

This study is a retrospective cohort analysis of patients treated for head and neck mucoepidermoid carcinoma at the RMH between 2005 and 2022. Patient demographics, treatment, pathology, in particular the AFIP histological grading of the primary tumour, and outcomes were collected and tabulated. Time to recurrence was recorded, and survival outcomes were calculated with Kaplan-Meier method. Comparisons were made on different histological grading and regional metastases.

RESULTS

Thirty-three patients were identified and thirty met the inclusion criteria. There was an age range of 18-77 years (median 54 years) with no significant sex difference. Our patients had a 94% 5-year survival and an 86% 10-year survival. Thirteen patients had elective neck dissection and 2 out of 13 (15%) of the patients had positive neck disease. Of the two patients with regional metastasis, the primary tumour was graded as intermediate and low grade. No high-grade MEC patients had regional metastasis.

CONCLUSION

Mucoepidermoid carcinoma of the head and neck is associated with a good disease-specific and overall survival despite the presence of regional metastasis. The AFIP histological grading system did not have a statistically significant correlation to the incidence of nodal metastasis.

[Why is the histomorphological diagnosis of small salivary gland tumours so much more difficult?]

There is a widespread impression among clinicians and pathologists that the histomorphological diagnosis of minor salivary gland tumours is more difficult and more frequently misdiagnosed than that of major glands. This is based on subjective clinical impression; scientific proof of and potential reasons for this difference are lacking. We identified 14 putative clinical, histopathological and combined clinical-histological reasons and four consequences, which together could explain the perceived greater difficulty of diagnosing minor gland tumours. We performed a thorough literature search and a statistical comparison of data from a personal large consultation series (biased for "difficult" cases) with cumulated data from a routine, unselected (non-consultation) series from the literature. Through this comparison, we could prove with statistical significance a series of reasons and consequences for this greater diagnostic difficulty in minor glands. Frequent incisional biopsies, almost obligatory low-grade bland cytology in malignant tumours and insufficient clinical-pathological communication emerged as the most important reasons. The special anatomic location of the hard palate contributes to further diagnostic difficulties, such as tumour necrosis, mucosal ulceration, pseudoinvasion and the "tumoural-mucosal fusion" phenomenon. Knowledge of these pitfalls in clinic and pathology can help overcome these difficulties and reduce the misdiagnosis rate in minor gland tumours. Our findings result in a series of recommendations both for the clinic and pathology.

Pleomorphic Adenoma of Submandibular Gland in a Pediatric Case

Neoplasms of the salivary glands are relatively uncommon, with varied histologic subtypes. Only 5% of these occur in the pediatric age group. The submandibular gland tumors account for just 11.5% of pediatric salivary gland tumors. Few studies have reported the occurrence of pleomorphic adenoma arising in submandibular gland in a child. We describe a case of pleomorphic adenoma affecting submandibular gland in a girl aged eleven years and provide a brief review of current literature. Thorough diagnostic evaluation is required, considering the diverse differential diagnoses of pediatric submandibular masses. Although benign, recurrence and malignant transformation are pertinent concerns in pleomorphic adenoma, especially in a child, considering long life expectancy.

Secretory carcinoma of the salivary gland is rich in lactoferrin: a possible lactational-like differentiation?

PURPOSE

It has been hypothesised that secretory carcinoma of the salivary gland (SCsg) might have a lactational-like differentiation. Therefore, we aimed to assess the immunoexpression of breast hormonal receptors and milk-related proteins in cases of SCsg and other salivary gland tumours with prominent secretory activity.

METHODS

Immunohistochemistry against prolactin and growth hormone receptors, lactoferrin, human milk fat globule 1, MUC 1 and MUC4 was performed in twelve cases of SCsg and 47 other salivary gland tumours.

RESULTS

Most cases of SCsg were negative for prolactin and growth hormone receptors. All cases of SCsg showed enhanced membranous-cytoplasmic staining for human milk fat globule 1, a pattern seen in other tumour groups. Only SCsg showed widespread strong staining for lactoferrin, concomitantly in the cell compartment and secretion. The other positive tumour types exhibited restricted staining. MUC1 and MUC4 showed no distinct pattern of expression.

CONCLUSION

Although SCsg failed to demonstrate a complete lactational-like differentiation, lactoferrin showed a distinctive expression pattern in SCsg compared to other tumour types, which makes it a good marker to help in its differential diagnosis.

Survival outcomes, prognostic factors, and effect of adjuvant radiotherapy and prophylactic neck dissection in salivary acinic cell carcinoma: A prospective multicenter REFCOR study of 187 patients

BACKGROUND

Acinic cell carcinomas (AciCCs) are malignant tumours of the salivary glands. The aim of this work was to analyse data from the national REFCOR multicenter cohort (i) to investigate the prognostic factors influencing survival outcomes in AciCC, (ii) to assess the impact on survival of postoperative radiotherapy (RT) in patients treated for AciCC without high-grade transformation and (iii) to explore the prognostic impact of prophylactic neck dissection (ND) in patients treated for AciCC of the major salivary glands.

PATIENTS AND METHODS

Data from all the patients treated for salivary AciCC between 2009 and 2020 were extracted from the REFCOR database. Survival outcomes and prognostic factors influencing Disease-Free Survival (DFS) and Overall Survival (OS) were investigated using univariate and multivariate analyses. Propensity score matching was used to assess the impact of postoperative RT and prophylactic ND on DFS.

RESULTS

A total of 187 patients were included. After a median follow-up of 53 months, their 5-year OS and DFS rates were 92.8% and 76.2%, respectively. In multivariate analysis, male sex, older age, higher T and N status, and high grade were independently associated with a worse DFS. In the subpopulation analysed after propensity score matching, patients with cN0 AciCC without high-grade transformation who were treated by surgery and RT did not have an improved DFS compared to patients who were treated by surgery alone (hazard ratio (HR) = 0.87, p = 0.8). Factors associated with nodal invasion were T3-T4 status and intermediate/high histological grade. After propensity score matching, prophylactic ND was associated with a trend toward a better DFS (HR = 0.46, p = 0.16).

CONCLUSIONS

These results suggest that (i) long-term follow-up (>5 years) should be considered in patients with AciCC, (ii) treatment by surgery alone could be an option in selected cN0 patients with AciCC without high-grade transformation and (iii) prophylactic ND may be considered preferentially in patients with T3-T4 status and/or intermediate/high histological grade.

Comparative analysis of benign and malignant parotid gland tumors: A retrospective study of 992 patients

OBJECTIVE

We analyzed and compared the clinical characteristics of benign and malignant parotid gland tumors.

PATIENTS AND METHODS

A total of 992 patients who underwent surgical treatment for parotid gland tumors from January 2010 to December 2020 were included in this study. This study population was subdivided into benign (n = 812, 81.9 %) and malignant parotid gland tumors (n = 180, 18.1 %).

RESULTS

Pleomorphic adenoma is the most common benign tumor and mucoepidermoid carcinoma is the most common malignant tumor. The patients with malignant parotid gland tumors were older than the patients with benign lesions. The duration of symptoms was longer in patients with benign parotid gland tumors compared to those with malignant lesions. The size of the malignant tumors was larger than that of the benign lesions. Preoperative fine-needle aspiration cytology had a diagnostic sensitivity of 50.3 %, diagnostic specificity of 98.7 %, a positive predictive value of 89.5 %, a negative predictive value of 89.9 %, and accuracy of 89.9 % for diagnosing malignant parotid gland tumors. For benign parotid gland tumors, superficial parotidectomy was most frequently performed, and for malignant parotid gland tumors, total parotidectomy was most frequently performed. Facial palsy was observed in 19.4 % of the patients with malignant parotid gland tumors compared to 5.4 % of those with benign tumors.

CONCLUSION

The clinical features of benign and malignant parotid gland tumors showed differences in age, symptoms, duration of symptoms, size and site of the parotid tumors, surgical procedures, and postoperative facial nerve palsy.

Clinical outcomes and cost-effectiveness of superficial parotidectomy versus extracapsular dissection of the parotid gland: a single-centre retrospective study of 161 patients

Improvements in preoperative diagnostics and intraoperative techniques have made the surgical excision of benign parotid gland tumours less invasive. Extracapsular dissection (ECD) has become more popular in comparison to superficial parotidectomy (SP), the gold standard. Although clinical outcomes have been reported, reports on cost-effectiveness are limited. The aim of this retrospective study was to analyse the surgical outcomes and cost-effectiveness of ECD versus SP in benign parotid tumour surgery. A retrospective cohort of 161 patients treated between 2012 and 2020 was collected. Data concerning demographics, clinical outcomes, and cost-efficiency were recorded. Analysis of the 161 unilateral parotidectomy cases (59 SP, 102 ECD) showed a significantly longer operation time, anaesthesia time, and length of stay for SP patients (all P < 0.001). Regarding postoperative complications, transient facial nerve weakness (P < 0.001) and haematoma formation (P = 0.016) were more prevalent in the SP patients. The frequency of positive margins was lower for SP (P = 0.037). No case of recurrence was identified with either technique. ECD showed excellent clinical outcomes as well as a reduction in complications when compared to SP. ECD is a viable alternative for superficial benign parotid gland tumours after thorough preoperative clinical, pathological, and radiological examination. The reduction in operation, anaesthesia, and hospitalization times with ECD is likely to result in a gain in cost-effectiveness.

Discriminating between benign and malignant salivary gland tumors using diffusion-weighted imaging and intravoxel incoherent motion at 3 Tesla

PURPOSE

The purpose of this study was to retrospectively evaluate the diagnostic performances of diffusion-weighted imaging (DWI) and intravoxel incoherent motion (IVIM) for discriminating between benign and malignant salivary gland tumors (SGTs).

MATERIALS AND METHODS

Sixty-seven patients with 71 SGTs who underwent MRI examination at 3 Tesla were included. There were 34 men and 37 women with a mean age of 57 ± 17 (SD) years (age range: 20-90 years). SGTs included 21 malignant tumors (MTs) and 50 benign SGTs (33 pleomorphic adenomas [PAs] and 17 Warthin's tumors [WTs]). For each SGT, DWI and IVIM parameters, mean, skewness, and kurtosis of apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo-diffusion coefficient (D*) and perfusion volume fraction (f) were calculated and further compared between SGTs using univariable analysis. Areas under the curves (AUC) of receiver operating characteristic of significant parameters were compared using the Delong test.

RESULTS

Significant differences in ADC_mean, D_mean and D*_mean were found between SGTs (P < 0.001). The highest AUC values were obtained for ADC_mean (0.949) for identifying PAs and D*_mean (0.985) for identifying WTs and skewness and kurtosis did not outperform mean. To discriminate benign from malignant SGTs with thresholds set to maximize Youden index, IVIM and DWI produced accuracies of 85.9% (61/71; 95% CI: 75.6-93.0) and 77.5% (55/71; 95% CI: 66.0-86.5) but misdiagnosed MTs as benign in 28.6% (6/21) and 61.9% (13/21) of SGTs, respectively. After maximizing specificity to 100% for benign SGTs, the accuracies of IVIM and DWI decreased to 76.1% (54/71; 95% CI: 64.5-85.4) and 64.8% (46/71; 95% CI: 52.5-75.8) but no MTs were misdiagnosed as benign. IVIM and DWI correctly diagnosed 66.0% (33/50) and 50.0% (25/50) of benign SGTs and 46.5% (33/71) and 35.2% (25/71) of all SGTs, respectively.

CONCLUSION

IVIM is more accurate than DWI for discriminating between benign and malignant SGTs because of its advantage in detecting WTs. Thresholds set by maximizing specificity for benign SGTs may be advantageous in a clinical setting.

[Frozen section biopsy for tumors of the submandibular triangle]

BACKGROUND

Diagnosis and treatment of submandibular lesions is challenging. Carcinomas, which frequently occur, should be surgically removed with sufficient safety margins, while simultaneously protecting functional structures. In particular, the preservation of neuronal structures with simultaneous tumor control suggests that single-stage concepts are appropriate, although they are not yet established. The aim of this study was to evaluate intraoperative frozen section biopsy as a possible basis for a one-stage surgical concept to thus prevent functional alterations by reoperation.

METHODS

A total of 114 consecutive patients with neoplastic lesions in whom the type of lesion could not be determined after ENT examination and imaging were included in the study. Patients with a known history of carcinoma or evidence of an acute inflammatory or carcinogenic primary lesion in the ENT examination and/or imaging were excluded. An intraoperative frozen section biopsy was performed to determine the presence of a carcinoma. Patient-related data and the reliability of the frozen section result were recorded comparatively.

RESULTS

Intraoperative frozen section biopsy was performed in a total of 114 patients. Carcinomas were diagnosed with a sensitivity of 87% and a specificity of 100%. There would thus not have been unnecessary radical surgery in a one-stage approach. In 26 of 30 patients with carcinoma, a second operation could have been avoided.

CONCLUSION

Intraoperative frozen section biopsy is potentially an important method to histologically confirm carcinomas and avoid two-stage procedures. The absence of false-positive findings would have prevented an unnecessary radical procedure in 100% of patients.

Incidence and clinical outcome of primary carcinomas of the major salivary glands: 10-year data from a population-based state cancer registry in Germany

PURPOSE

The aim of this project was to provide an overview of the epidemiology of primary salivary gland carcinomas (SGC) in terms of incidence, distribution of clinicopathological features and survival in one of the largest cancer registries in Europe.

METHODS

Data were collected from patients with SGC of the major salivary glands registered in the population-based state cancer registry (Landeskrebsregister LKR) in North Rhine-Westphalia (NRW), Germany from 01/01/2009 to 12/31/2018. Age standardization of incidence was performed and relative survival estimates were computed by sex, histological group, age group and T-, N-, and M-stage.

RESULTS

A total of 1680 patients were included in this analysis. The most frequent tumor localization was the parotid gland (78%). Adenocarcinoma (not otherwise specified) was the most common tumor entity (18.5%). Most tumors were found in stages T1-T3 (29% T1; 29% T2; 28% T3). The age-standardized incidence rate (ASR) for SGC was 0.65/100,000 and remained stable during the observation period. There was an age-dependent incidence increasing especially from the age 70 years and onwards. The overall 5-year relative survival (RS) for all patients with SGC was 69.2%. RS was 80-95.6% for T1-2 stage tumors, 60.3% for T3, 47.3% for T4 stage, 87.4% for N0 and 51.2% for N1-2, 74.4% for M0 and 44.9% for M1.

CONCLUSION

Age-standardized incidence for SGC has been stable for the observed 10-year period. Smaller tumors and those without lymph node or distant metastases had a better RS than more advanced tumors.

Salivary Gland Polymorphous Adenocarcinoma: Clinicopathological Features and Gene Alterations in 36 Japanese Patients

OBJECTIVES

Polymorphous adenocarcinoma (PAC) is a common intraoral minor salivary gland carcinoma in Western countries but is extremely rare in Japan. The current study aimed to characterize the clinicopathological features and status of molecular alterations of PAC-associated genes, such as (e.g., PRKD1/2/3, ARID1A, and DDX3X) in a large cohort of Japanese patients with PAC.

MATERIALS AND METHODS

We examined the cases of 36 Japanese patients with salivary gland PAC and 26 cases involving histopathological mimics. To detect gene splits, fluorescence in situ hybridization was carried out for PAC-associated genes. Additionally, we applied a SNaPshot multiplex assay to identify PRKD1 hotspot mutations.

RESULTS

This study revealed the indolent clinical course of PAC with a high 10-year overall survival rate (92.9%), accompanied by occasional local recurrences and cervical lymph node metastasis (both 23.3%). Twenty cases (55.6%) of PAC (but none of the mimics) exhibited alterations in at least one PAC-associated gene. Rearrangement of PAC-associated genes and PRKD1 E710D were identified in 17 (47.2%) and 4 (11.1%) cases, respectively; one case showed coexisting PRKD3 split and PRKD1 E710D. In the multivariate analysis, high clinical stage (P=0.0005), the presence of prominent nucleoli (P=0.0003), and ARID1A split positivity (P=0.004) were independent risk factors for disease-free survival.

CONCLUSION

Japanese patients with PAC showed clinicopathological features similar to those reported in Western countries. This study disclosed that PAC-associated genetic alterations were common and specific findings in PACs. The diagnostic role and possible prognostic significance of PAC-associated genetic alterations in PACs were suggested.

Sine Qua Non: Oncocytoma

Oncocytomas of the salivary gland are uncommon neoplasms that are characterized by polygonal cells with abundant granular eosinophilic cytoplasm and relatively uniform nuclei. They are benign in nature and have a low recurrence rate with complete surgical excision. Though uncommon, oncocytic and clear cell variants of malignant tumors may histologically mimic oncocytomas and identification of their distinguishing features is essential. A classic example of an oncocytoma is discussed.

Targeted molecular profiling of salivary duct carcinoma with rhabdoid features highlights parallels to other apocrine and discohesive neoplasms: which phenotype should drive classification?

BACKGROUND

Salivary duct carcinoma with rhabdoid features (SDC-RF) is a recently-described salivary gland tumor that bears striking histologic similarity to lobular carcinoma of the breast. While this tumor has an apocrine phenotype that supports classification as a variant of SDC, it infrequently arises in association with conventional SDC. Furthermore, discohesive architecture can be seen in non-apocrine salivary carcinomas, raising the possibility that discohesive growth should define a separate entity. In this study, we aimed to perform comprehensive molecular profiling of SDC-RF to better understand its pathogenesis and classification.

METHODS

We documented the clinicopathologic features of 9 cases of SDC-RF and performed immunostains including AR, GCDFP, and e-cadherin on all cases. We also performed targeted next generation sequencing (NGS) panels on 7 cases that had sufficient tissue available.

RESULTS

The SDC-RF represented 8 men and 1 woman with a median age of 67 years (range 63-83 years) and included 6 parotid, 2 buccal, and 1 submandibular primary. All tumors were uniformly composed of discohesive cells with abundant eosinophilic cytoplasm; signet-ring cell features were seen in 2 cases. All tumors were also positive for AR (100%) and GCDFP (100%), and 7 tumors (78%) displayed lost or abnormal e-cadherin. NGS highlighted concomitant PIK3CA and HRAS mutations in 4 tumors, with additional cases harboring TP53, PTEN, and AKT1 mutations. Furthermore, CDH1 alterations were seen in 6 cases, including a novel CDH1::CORO7 fusion. Among 5 patients with follow-up available, 3 (60%) developed local recurrence and widespread distant metastasis and died of disease at a median 20 months (range 10-48 months).

CONCLUSIONS

Overall, our findings confirm frequent CDH1 mutations and e-cadherin inactivation in SDC-RF, similar to discohesive tumors from other sites. We also highlight an apocrine molecular profile similar to conventional SDC. However, occasional AKT1 mutation and signet-ring features suggest SDC-RF may also be related to mucinous adenocarcinoma. As more salivary tumors with discohesive growth are identified, it may become clearer whether SDC-RF should remain in the SDC family or be recognized as a separate entity.

Evaluation of pembrolizumab monotherapy in patients with previously treated advanced salivary gland carcinoma in the phase 2 KEYNOTE-158 study

AIM

We evaluated pembrolizumab monotherapy in patients with advanced salivary gland carcinoma on the phase 2 KEYNOTE-158 study (NCT02628067).

METHODS

Eligible patients had histologically/cytologically confirmed advanced salivary gland carcinoma with prior failure or intolerance to standard therapy, measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1., and ECOG performance status 0-1. Patients were enrolled irrespective of tumour PD-L1 expression. Patients received pembrolizumab 200 mg Q3W for up to 35 cycles (∼2 years). Radiographic imaging occurred every 9 weeks through month 12, then every 12 weeks. PD-L1 positivity was defined as combined positive score ≥1 (evaluated using PD-L1 IHC 22C3 pharmDx). The primary endpoint was objective response rate per RECIST v1.1.

RESULTS

In total, 109 patients were enrolled (PD-L1-positive, 25.7%). At the data cutoff (October 5, 2020), median follow-up was 53.3 (range, 50.8-56.3) months. Objective response rate was 4.6% (95% CI, 1.5-10.4%) among all patients (complete response, n = 1; partial response, n = 4) and was 10.7% (95% CI, 2.3-28.2%) in patients with PD-L1-positive disease and 2.6% (95% CI, 0.3-9.1%) in patients with PD-L1-negative disease. Duration of response was ≥24 months for all 5 responders; median duration of response was not reached (range, 25.1-49.8+ months). Median progression-free survival and overall survival were 4.0 (95% CI, 2.6-4.2) and 21.1 (95% CI, 15.9-25.5) months, respectively. Treatment-related adverse events occurred in 75.2% (grade 3-4, 15.6%; grade 5, 0%) of patients. Immune-mediated adverse events occurred in 22.0% of patients (grade 3, 5.5%; grade 4-5, 0).

CONCLUSIONS

A small subset of patients with advanced salivary gland carcinoma treated with pembrolizumab had a response; all had response duration ≥2 years. The safety profile of pembrolizumab was manageable.

Application of the Milan system for reporting salivary gland cytopathology using cell blocks

The Milan system for reporting salivary gland cytopathology (MSRSGC) is a novel standardized classification tool for salivary gland cytology specimens based on the use of direct smears. Formalin-fixed paraffin-embedded (FFPE) cell blocks facilitate the use of ancillary studies, leading to improved diagnostic accuracy. However, the application of the MSRSGC with only cell blocks has not been well established. Consecutive cohort of all parotid gland cytology specimens between 01/01/2018 and 30/06/2021 was performed. All cytology specimens were processed into cell blocks only. Cytologic diagnoses were classified prospectively according to the MSRSGC categories. The risk of malignancy (ROM) for each diagnostic category and the diagnostic performance were calculated. A total of 230 FNA samples from 221 patients were identified, including 47% and 78.4% with surgical or clinical follow-up, respectively. The ROMs based on surgical follow-up for the non-diagnostic, non-neoplastic, AUS, neoplasm: benign, SUMP, SFM and malignant categories were 21.4%,0%,50%,0%,30%,100% and 100%, respectively. The ROMs based on the clinical follow-up for these categories were 7.3%,0%,37.3%,0%,27.3%,100% and 100%, respectively. Following surgical excision, all Milan IVa category samples were confirmed as benign, and all Milan V and VI category samples were confirmed as malignant. This study validates the application of the MSRSGC with the sole use of FFPE cell blocks. The diagnostic accuracy of MSRSGC is high and compares favorably to other institutions using traditional cytology assessment methods. Furthermore, FNA results using this technique enabled to provide optimal patient management based on the ROM of the different Milan system categories.

[Radiation therapy of malignant salivary gland tumors]

Due to their rarity, histologic heterogeneity, and localization, treatment of malignant salivary gland tumors requires an interdisciplinary approach. First-line treatment includes complete tumor resection. Postoperative radiation therapy is advised in patients with risk factors, i.e., incomplete tumor resection, high-grade tumors, or perineural invasion. Definitive radiation therapy is only advised for inoperable tumors because of significantly lower local control and survival rates when compared to combined surgery and radiation therapy. In radiation oncology, modern techniques such as intensity-modulated radiation therapy (IMRT) or particle therapy with heavy ions (i.e., C12) have led to improved outcomes in the treatment of head and neck tumors, especially of adenoid cystic carcinomas. Given the biological and physical benefits of particles, particle therapy, particularly carbon ion radiation, is a promising therapeutic approach for salivary gland tumors that will be further investigated in prospective clinical studies.

Epithelial-myoepithelial carcinoma of the maxillofacial and sinonasal region: a systematic review of presenting characteristics, treatment modalities, and associated outcomes

Epithelial-myoepithelial carcinoma (EMC) is a rare salivary gland malignancy. Controversy exists in the literature regarding the effectiveness of treatment modalities employed in the management of EMC. This systematic review was undertaken to understand the presenting characteristics of EMC and identify the most common treatment modalities and their associated outcomes, in order to help guide an evidenced-based approach to the algorithm of care. The MEDLINE (PubMed) and Embase databases were searched (up to February 23, 2022), and the review was performed in accordance with the PRISMA statement. Fifty-seven studies (51 case reports and six case series) describing 91 cases of EMC were included in this review. In the included studies, a slow-growing painless mass was the most common presenting clinical feature. EMC was most frequently treated with surgery alone (65%). Local disease recurrence occurred in 24% of the cases and metastatic disease in 11%. A positive surgical margin was found to be associated with a higher risk of recurrence (P < 0.001), while adjuvant radiotherapy was associated with a decreased risk of local disease recurrence (P = 0.034). Metastatic disease and multimodal therapy were found to be associated with decreased disease-free and overall survival (all P < 0.05). The current literature supports surgery with clear margins as the mainstay of treatment for EMC of the salivary and seromucous glands of the head and neck. In certain situations, radiotherapy may improve disease-free survival.

Distribution and Frequency of Salivary Gland Tumours: An International Multicenter Study

BACKGROUND

Salivary gland tumours (SGT) are a relatively rare group of neoplasms with a wide range of histopathological appearance and clinical features. To date, most of the epidemiological studies on salivary gland tumours are limited for a variety of reason including being out of date, extrapolated from either a single centre or country studies, or investigating either major or minor glands only.

METHODS

This study aimed to mitigate these shortcomings by analysing epidemiological data including demographic, anatomical location and histological diagnoses of SGT from multiple centres across the world. The analysed data included age, gender, location and histological diagnosis from fifteen centres covering the majority of the world health organisation (WHO) geographical regions between 2006 and 2019.

RESULTS

A total of 5739 cases were analysed including 65% benign and 35% malignant tumours. A slight female predilection (54%) and peak incidence between the fourth and seventh decade for both benign and malignant tumours was observed. The majority (68%) of the SGT presented in major and 32% in the minor glands. The parotid gland was the most common location (70%) for benign and minor glands (47%) for malignant tumours. Pleomorphic adenoma (70%), and Warthin's tumour (17%), were the most common benign tumours whereas mucoepidermoid carcinoma (26%) and adenoid cystic carcinoma (17%) were the most frequent malignant tumours.

CONCLUSIONS

This multicentre investigation presents the largest cohort study to date analysing salivary gland tumour data from tertiary centres scattered across the globe. These findings should serve as a baseline for future studies evaluating the epidemiological landscape of these tumours.

Reconstruction and analysis of the aberrant lncRNA-miRNA-mRNA network based on competitive endogenous RNA in adenoid cystic carcinoma of the salivary gland

Background

The aim of this work was to investigate the competing endogenous RNA (ceRNA) network in adenoid cystic carcinoma of the salivary gland (SACC).

Methods

Differentially expressed lncRNAs (DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs) between cancer tissues and normal salivary gland (NSG) in ACC were identified using data from the Gene Expression Omnibus (GEO) database. Functional annotation and pathway enrichment analysis of DEmRNAs were performed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The miRNAs that are targeted by lncRNAs were predicted using miRanda and PITA, while the target mRNAs of miRNAs were retrieved from miRanda, miRWalk, and TargetScan. A protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and then we constructed the lncRNA-miRNA-mRNA networks of ACC.

Results

Differentially expressed RNAs were identified in SACC. Upon comparing cancer tissues and NSG tissues, 103 upregulated and 52 downregulated lncRNAs and 745 upregulated and 866 downregulated mRNAs were identified in GSE88804; in addition, 39 upregulated and 43 downregulated miRNAs were identified in GSE117275. GO enrichment analyses revealed that the most relevant GO terms were regulation of transcription DNA-templated, transcription DNA-templated, and cell division. KEGG pathway enrichment analysis showed that differentially expressed genes (DEGs) were mainly enriched in the cell cycle, pathways in cancer, PI3K-Akt signaling pathway, breast cancer, and microRNAs in cancer. The PPI network consisted of 27 upregulated and 54 downregulated mRNAs. By constructing ceRNA network, NONHSAT251752.1-hsa-miR-6817-5p-NOTCH1, NONHSAT251752.1-hsa-miR-204-5p/hsa-miR-138-5p-CDK6 regulatory axises were identified and all genes in the network were verified by qRT-PCR.

Conclusions

The present study constructed ceRNA networks in SACC and provided a novel perspective of the molecular mechanisms for SACC.

Hyalinizing clear cell carcinoma of minor salivary glands: A case report with uncommon presentation

Hyalinizing clear cell carcinoma (HCCC) is a rare malignant neoplasm that commonly arises in the palate, whose occurrence in other intraoral sites is extremely uncommon. We present a case of a 74 years old afro-descendant female presenting an asymptomatic swelling in the lingual region of teeth 32, 33 and 34, with four months of Evolution, promoting an area of bone resorption with imprecise margins. Incisional biopsy revealed proliferative nests of clear cells within a hyalinized fibrous connective tissue. Tumor cells showed immunohistochemical positivity for AE1/AE3, CK7, p63 and ki67 (30%), but negativity for CK14, CK19 and α-SMA. The final diagnosis was HCCC. The tumor was subjected to surgical resection and no recurrence was observed after 16 months. CCCH is a low-grade malignant tumor that must be differentiated from other malignant clear cell tumors, including epithelial-myoepithelial carcinoma, myoepithelial carcinoma, mucin-depleted mucoepidermoid carcinoma and metastatic renal clear cell carcinoma. Immunohistochemistry is a useful tool to achieve the correct diagnosis and provide the proper therapy for the tumor.

[Salivary gland tumors-an overview : Advances in molecular characterization: Part I]

In den letzten Jahren hat die Charakterisierung der Speicheldrüsenkarzinome einen großen Wandel durchlebt. Morphologisch definierte Entitäten konnten zu einem Großteil auch molekular mit einem oftmals distinkten Genotyp charakterisiert werden. Der erste Teil des Artikels gibt einen Überblick über die Fortschritte der molekularen Charakteristiken des Mukoepidermoidkarzinoms, adenoid-zystischen Karzinoms, Azinuszellkarzinoms, des sekretorischen und intraduktalen Karzinoms sowie des hyalinisierenden klarzelligen Karzinoms. Der molekulare Genotyp kann dabei insbesondere bei der Klassifizierung ungewöhnlicher morphologischer Varianten von großem Nutzen sein. Rekurrente NTRK- oder RET-Genfusionen können dabei nicht nur als diagnostisches Hilfsmittel, sondern auch für eine potenzielle gezielte Therapie genutzt werden.

Microsecretory Adenocarcinoma of Salivary Glands: An Expanded Series of 24 Cases

Microsecretory adenocarcinoma (MSA) is a recently described salivary gland tumor with a characteristic histologic and immunophenotypic profile and recurrent MEF2C-SS18 fusions. Because only six cases of MSA have been published, its complete clinicopathologic spectrum is unclear, and its biologic behavior has not been documented. Here, we present an updated and expanded experience of 24 MSA cases. All cases of MSA were obtained from the authors' files. Immunohistochemistry for S100, SOX10, p63, p40, SMA, calponin, and mammaglobin was performed. Molecular analysis was performed by targeted RNA sequencing, SS18 break apart fluorescence in situ hybridization, and/or reverse transcriptase polymerase chain reaction for MEF2C-SS18 fusion. Clinical follow-up was obtained from medical records. A total of 24 MSA cases were collected, from 13 women and 11 men, ranging from 17 to 83 years (mean 49.5 years). The vast majority (23 of 24) arose in the oral cavity, with the palate (n = 14) and buccal mucosa (n = 6) as the most frequent subsites. Tumors showed consistent histologic features including: (1) microcystic tubules, (2) flattened intercalated duct-like cells, (3) monotonous oval hyperchromatic nuclei, (4) abundant basophilic luminal secretions, (5) fibromyxoid stroma, and (6) circumscribed borders with subtle infiltration. The tumors were very consistently positive for S100 (24 of 24), p63 (24 of 24), and SOX10 (14 of 14) and negative for p40 (0 of 21), calponin (0 of 12) and mammaglobin (0 of 16), while SMA (4 of 20) was variable. MEF2C-SS18 fusion was demonstrated in 21 of 24 cases; in the remaining 3 cases with insufficient RNA, SS18 break apart FISH was positive. Treatment information was available in 17 cases, all of which were managed with surgery only. In 14 cases with follow-up (1-216 months, mean 30), no cases recurred or metastasized. MSA is a distinct salivary gland neoplasm with remarkably consistent clinical, histologic, immunophenotypic, and genetic features that generally behaves in an indolent manner following surgery alone. These observations solidify MSA as a unique, low-grade salivary gland carcinoma that warrants inclusion in the next version of the WHO classification of head and neck tumors.

Diagnosis and management of malignant sublingual gland tumors: a narrative review

OBJECTIVE

In this article we review the literature on the malignant sublingual gland tumors from a surgical perspective.

BACKGROUND

Sublingual gland tumors occur with a very low incidence and most are malignant tumors. The extent of treatment, clinical outcomes and prognosis of malignant sublingual gland tumors have not been well defined, due to the rarity of this disease.

METHODS

A database search using Web of Science (https://webofknowledge.com/) and PubMed (https://pubmed.ncbi.nlm.nih.gov/) was conducted. The following keywords were used in the search: "sublingual gland tumor", AND "malignancy".

CONCLUSIONS

Although the sublingual glands are among the major salivary glands, they share common anatomical characteristics with minor salivary gland tumors. Therefore, the tumors from the sublingual gland may have different clinical behaviors from the other major salivary gland tumors. The sublingual glands are small without a true surrounding capsule of the glands; the extra-parenchymal extension is very common in sublingual gland tumors. Furthermore, the sublingual glands are located in close proximity to the lingual nerve, the submandibular gland-duct system and the mandible. Thus, the surgical approach to the malignant sublingual gland tumor should include the adequate management of neighboring structures. In addition, adjuvant radiation therapy provides a survival benefit for patients with malignant sublingual gland tumors, which have adverse features. This article summarizes the clinical characteristics and unique features of malignant sublingual gland tumors based on previous reports, and provides clinical information regarding the sublingual gland tumors to increase awareness of primary physicians as well as patients.

A Single-Arm, Prospective, Phase II Study of Cisplatin Plus Weekly Docetaxel as First-Line Therapy in Patients with Metastatic or Recurrent Salivary Gland Cancer

Purpose

Salivary gland cancers (SGCs) are relatively rare but comprise various histologic subtypes, which complicates design of prospective trials. Systemic chemotherapy plays a limited role in treatment of SGCs, but cisplatin and docetaxel showed efficacy in a previous preclinical study. Here, we conduct a prospective, phase II study to evaluate the efficacy and toxicities of cisplatin plus weekly docetaxel in patients with metastatic or recurrent SGC.

Materials and Methods

We included patients with histologically confirmed SGCs of the following subtypes: mucoepidermoid carcinoma, adenocarcinoma, ductal carcinoma, or adenoid cystic carcinoma. Patients had no prior systemic chemotherapy for metastatic or recurrent tumors and at least one measurable lesion. Patients were treated with docetaxel 35 mg/m² (D1, 8) and cisplatin 70 mg/m² (D1) every 21 days.

Results

Forty-one patients were enrolled between April 2014 and October 2020. The median age was 58 years (range, 32 to 73 years). The most common histologic subtype was adenoid cystic carcinoma (63.4%), followed by ductal carcinoma (24.4%). The most common metastatic site was the lung (75.6%). The median treatment cycle was 5.5 (range, 3 to 8), and the objective response rate was 46.3%, with three complete responses. The median duration of response was 6.8 months (interquartile range, 4.0 to 10.2). The progression-free survival and overall survival were 9.4 months (95% confidence interval [CI], 8.4 to 10.5) and 28.2 months (95% CI, 22.7 to 33.6), respectively. There were no treatment-related deaths. The most common grade 3/4 adverse events were neutropenia (4.9%) and fatigue (4.9%).

Conclusion

Cisplatin plus weekly docetaxel is effective and tolerable with manageable toxicity as first-line therapy in patients with metastatic or recurrent SGC.

Outcomes of patients with minor salivary gland mucoepidermoid carcinoma of the palate undergoing submental flap reconstruction following radical resection

OBJECTIVE

To investigate the outcomes of patients with mucoepidermoid carcinoma of the palate undergoing pedicled facial-submental artery island flap (FSIF) reconstruction following resection.

PATIENTS AND METHODS

41 patients with early stage disease and 9 patients with advanced-stage disease underwent radical excision and neck dissection. 37 IIb, 4 class IIa and 9 IIIb maxillary defects were reconstructed with FSIF, folded FSIF or folded FSIF with titanium mesh respectively. The skin paddles were 3 × 8 to 5 × 15 cm and 3 × 8 to 5 × 14 cm, respectively. 5 patients with high grade disease were treated with cobalt 60 adjuvant radiotherapy after operation.

RESULTS

One flap failure occurred, yielding a success rate of 98.0% in the reconstruction of palate II and III defects with FSIF or titanium mesh. The patients were seen for follow-up for 16-60 months postoperative. 76.0% patients alive with no disease (AND); 14.0% patients alive with disease (AD) and 10.0% died of disease (DD). Rates of AND, AD and DD differed significantly according to histopathologic grade and TNM stage (P < 0.001); rates of AND, AD and DD differed obviously according to necrosis of the tumors lymph node metastasis, and tumour cell anaplasia and treatment (P < 0.05).

CONCLUSIONS

Radical resection with wide safety margins of normal tissues including neck dissection is the mainstay of treatment modality. The patients with high grade disease should be treated with postoperative radiotherapy. The FSIF is a reliable and safe method for repairing Brown class II maxillary defects.

Immunohistochemical Reactivity of Prostate-Specific Membrane Antigen in Salivary Gland Tumors

Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein that is overexpressed in the prostate gland and prostate cancer. PSMA has been recently used in positron emission tomography/computed tomography (PET/CT) imaging and targeted alpha-radiation therapy (TAT) for prostate cancer. Recently, the tubarial gland, a type of minor salivary gland that is described as a new organ situated in the pharynx, is reported to express PMSA. Here, we studied the expression of PSMA in common benign and malignant salivary gland tumors. We performed immunohistochemistry for PSMA in 55 salivary gland tumors comprising 10 pleomorphic adenomas, 10 Warthin tumors, 9 basal cell adenomas, 9 adenoid cystic carcinomas, 9 mucoepidermoid carcinomas, and 8 salivary duct carcinomas. PSMA was expressed in 97% of benign tumors and 77% of malignant tumors. Moreover, PSMA was expressed in 59% of normal salivary glands adjacent to the tumor. PSMA is relatively expressed in salivary gland tumors and salivary glands. Therefore, salivary gland neoplasm, and normal salivary gland, possibly demonstrate the accumulation of PSMA in PET/CT. Thus, we need to monitor the side effects in the salivary glands during TAT for prostate cancer.

Risk stratification of parotid neoplasms based on intraoperative frozen section and preoperative fine needle aspiration cytology

PURPOSE

This study aims to determine the relationship of frozen section (FS) to final histology and determine how incorporating FS may change preoperative malignancy risk estimates based on preoperative fine needle aspiration cytology (FNAC). The secondary aim is to determine if FS is useful in influencing intraoperative decision-making.

METHODS

Retrospective review of 426 intraoperative FS for parotidectomies performed for primary parotid lesions.

RESULTS

Risk of malignancy with a benign FS was 2.5%, with indeterminate 36.1%, and with malignant 100%. Incorporating FS to fine needle aspiration for cytology helped to stratify malignancy risk especially in the Milan categories of atypia of undetermined significance, neoplasm of uncertain malignant potential and non-diagnostic categories, where a malignant FS increased malignancy risk significantly. FS was only able to identify 11% of high-risk histological subtypes for which a neck dissection would be recommended.

CONCLUSIONS

FS may be used to stratify malignancy risk intraoperatively but has limited utility in clinical decision-making to perform a neck dissection and more extensive parotid resection in high-risk histological subtypes.

Impact of tumor site on the prognosis of salivary gland neoplasms: A systematic review and meta-analysis

In numerous types of cancer, the primary tumor site can show a correlation with disease behavior and survival outcomes. In salivary gland tumors (SGTs) this association remains controversial. This study assessed the association between primary sites of SGTs and prognosis. Studies from five databases were assessed and a meta-analysis was performed using studies that presented 95 % confidence interval (95 % CI), hazard ratio (HR) and survival analysis. Gathered information from 46,361 patients showed that site had a prognostic impact on SGTs. Tumors involving minor salivary glands showed worse overall survival (HR = 1.60; 95 % CI = 1.17-2.19; p = 0.003), disease-specific survival (HR=1.63; 95 % CI = 1.12-2.37; p = 0.01), and cause-specific survival (HR=2.10; 95 % CI = 1.72-2.55; p = 0.00001). Tumors from major salivary glands showed better recurrence-free survival (HR=2.31; 95 % CI = 1.77-3.02; p = 0.00001), and locoregional control of disease (HR=2.66; 95 % CI = 1.20-5.91; p = 0.02). Our results showed that the primary site of SGTs has an impact on patient prognosis.

Clinical target volume design of postoperative intensity-modulated radiotherapy for major salivary gland tumours according to surgical principles: an innovative method

BACKGROUND

No international consensus has been reached regarding delineation of postoperative intensity-modulated radiotherapy (PO-IMRT) clinical target volumes (CTV) for major salivary gland carcinoma (SGC). The purpose of this article was to report our experience according to surgical principles.

METHODS

Between June 2010 and June 2018, 54 consecutive patients were enrolled. Reserved tissues around the margin of resection that were less than 5 mm from the invasive tumour edge before surgery were defined as high-risk clinical target volumes (CTV-HD), those less than 10 mm away were defined as medium-risk CTV (CTV1), and those 10-20 mm away were defined as low-risk CTV (CTV2), and were irradiated with 63-65 Gy, 59.5-61 Gy, and 45-54 Gy, respectively. Target volume distributions of reserved tissues were analysed and actuarial estimates of overall survival (OS), recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) were obtained with the Kaplan-Meier method.

RESULTS

In parotid gland tumours, the percentages of defined CTV-HD in the styloid process, mandibular ramus, posterior venter of the digastric muscle, carotid sheath and stylomastoid foramen reached 34.29%, 25.71%, 54.29%, 40.00%, and 37.10%, respectively. The median follow-up was 33 months (range, 5-98 months). The 3-year and 5-year Kaplan-Meier estimates of OS, RFS and DMFS were 85.4% and 77.8%, 97.4%, and 97.4%, and 82.0% and 82.0%, respectively.

CONCLUSIONS

It is feasible to delineate CTVs according to distances between various reserved tissues and the primary tumour edge before operation.

Trophoblast Cell Surface Antigen 2 (Trop-2) Protein is Highly Expressed in Salivary Gland Carcinomas and Represents a Potential Therapeutic Target

Treatment options for unresectable, recurrent or metastatic salivary gland carcinomas (SGC) are scarce. Trophoblast cell surface antigen 2 (Trop-2) is a transmembrane glycoprotein that is involved in a variety of oncogenic cell signaling pathways. Its potential as a target for the antibody-drug conjugate sacituzumab govitecan has already been demonstrated in different tumor entities. The United States Food and Drug Administration approved this antibody-drug conjugate for the treatment of metastatic triple-negative breast cancer. Here, we aimed to investigate Trop-2 protein expression in different entities of SGCs. We retrospectively reviewed the medical records of all patients that underwent surgery for a primary SGC in a tertiary referral center between 1990 and 2014. Immunohistochemical (IHC) staining for Trop-2 was performed and rated as negative, weak, moderate or high using a semiquantitative score. Additionally, representative cases were analyzed using MALDI-mass spectrometry (MS) imaging to confirm the IHC results. The cohort consisted of 114 tumors of the parotid gland (90.4%) and submandibular gland (9.6%). It mainly included mucoepidermoid, salivary duct and adenoid cystic carcinomas. In IHC samples, 44% showed high, 38% moderate and 10% weak expression rates of Trop-2. MALDI-MS imaging confirmed the presence of Trop-2 protein in 80% of the tested tumor samples. This is the first study to demonstrate that several types of SGC express Trop-2 with variable intensity. Since there are currently few systemic treatment options for advanced SGCs, Trop-2 represents a promising target for further clinical studies, for instance, with sacituzumab govitecan.

The radiologic (CT/MRI)-pathological correlations of the salivary duct carcinoma (SDC) with hyaline degeneration and peripheral nerve invasion

OBJECTIVES

Salivary duct carcinoma is an aggressive tumour commonly showing local invasion and/or nerve palsy. However, their CT/MRI findings, especially, regarding T2WI, and the diffusion-weighted-image (DWI), were not well known. In this study, we correlated the CT/MRI appearance and the pathological findings containing the nerve invasion cases such as a facial nerve.

METHODS

We reviewed 14 cases of SDC (parotid = 11, submandibular = 2, minor salivary gland = 1) pathologically proven peripheral nerve involvement. Their CT findings of all patient including dynamic contrast-enhancement study､MRI (n = 9) and DWI (n = 6) were also analyzed with histopathological correlation.

RESULTS

On contrast-enhanced CT, the solid component was moderately enhanced. On MRI, T2WI central low signal core (n = 6) with peripheral high intensity rim (n = 5) was frequently observed except heterogeneous low and high (n = 1), diffuse low (n = 1), and high (n = 1) signal cases. The hyaline degenerative area located in the tumour core was poorly enhanced. Eleven tumours had an ill-defined margin, reflecting invasive tumour growth. On DWI, they showed high signal [the central low and peripherally high (n = 4), and diffuse (n = 1), heterogeneously high signal (n = 1)]. The mean ADC value was 1.148 ~ 0.961 x 10-3 mm²/s. With pathological correlation, the central low signal area on T2WI reflected hyaline degeneration. The sites of gross nerve involvement were revealed as tubular or branching structures on CE-CT (n = 3), and MRI (n = 1).

CONCLUSIONS

(1) We frequently observed a central low signal area on T2WI/DWI in SDC. With histopathological correlation, it corresponded to the central hyaline degeneration with the peripheral viable tumour. 2) The gross nerve involvement might be detected as a strongly enhancement structure.

Diagnostic and prognostic value of miRNAs on salivary gland tumors: a systematic review and meta-analysis

PURPOSE

Different levels of miRNA expression have been described in salivary gland tumors as a potential diagnostic marker and predictor of survival. We systematically reviewed the literature to assess the diagnostic and prognostic value of miRNAs on salivary gland tumors.

METHODS

An electronic search was conducted in PubMed, Scopus, Embase, Cochrane, and Web of Science databases. In the meta-analysis, we assumed random-effects model with adjusted hazard ratio (HR) and 95% confidence intervals (95% CI). For prognostic studies, the risk of bias was assessed by Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI) and Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2) was utilized for diagnostic studies.

RESULTS

Gathered data from 1.131 patients in seven studies demonstrated that different levels of miRNA expression presented diagnostic and prognostic in SGTs. The meta-analysis showed that altered miRNA expression were associated with shortened survival (HR, 2.35, 95% CI, 1.77-3.10, P < .00001). For diagnostic meta-analysis, the overall pooled results for specificity and sensibility were 0.87-0.97 (95% CI, 0.72-1) and 0.68-0.91 (95% CI, 0.51-0.96), respectively.

CONCLUSION

MicroRNAs may be useful in prognostication of patients with SGTs; however, the diagnostic value of miRNAs in SGTs is still limited.

Actual applications of magnetic resonance imaging in dentomaxillofacial region

Magnetic resonance imaging (MRI) is a versatile imaging modality utilized in various medical fields. Specifically used for evaluation of soft tissues, with non-ionizing radiation and multiplanar sections that has provided great guidance to diagnosis. Nowadays, use of MRI in dental practice is becoming more pervasive, especially for the evaluation of head-and-neck cancer, detection of salivary gland lesions, lymphadenopathy, and temporomandibular joint disorders. Understanding the basic principles, its recent advances, and multiple applications in dentomaxillofacial region helps significantly in the diagnostic decision making. In this article, the principle of MRI and its recent advances are reviewed, with further discussion on the appearance of various maxillofacial pathosis.

Three-dimensional double-echo steady-state with water excitation magnetic resonance imaging to localize the intraparotid facial nerve in patients with deep-seated parotid tumors

PURPOSE

To assess the utility of three-dimensional double-echo steady-state with water excitation (3D-DESS-WE) imaging for localizing deep-seated parotid tumors in relation to the facial nerve.

METHODS

A prospective study comparing the surgical outcomes of parotidectomy with or without 3D-DESS-WE sequence is currently enrolling the patients. Magnetic resonance imaging data from the first 25 patients with 3D-DESS-WE sequence were reviewed. Visibility of the intraparotid facial nerve was independently assessed by two neuroradiologists. The diagnostic performance of the 3D-DESS-WE sequence for prediction of deep lobe involvement was compared with that of two conventional methods based on the retromandibular vein line (RMVL) and facial nerve line (FNL). The relationship between the tumor and the main trunk of the facial nerve was also evaluated on the 3D-DESS-WE sequence.

RESULTS

On 3D-DESS-WE images, the main trunk, temporofacial division, and cervicofacial division of the intraparotid facial nerve were visualized in 100% (25/25), 48% (12/25), and 36% (9/25) of patients, respectively. The diagnostic accuracy of the 3D-DESS-WE sequence for prediction of deep lobe involvement was 92% (23/25), which was significantly superior to that of the RMVL (68% [17/25]; p = 0.008) and FNL (64% [16/25]; p = 0.004) methods. The relationship between the tumor and the main trunk of the facial nerve was correctly predicted in 92% (23/25) of 3D-DESS-WE images.

CONCLUSION

By direct visualization of the facial nerve, the 3D-DESS-WE sequence improved the preoperative localization of the intraparotid facial nerve in deep-seated parotid tumors. This information may help better surgical planning for deep-seated parotid tumors.

Analysis of local invasion and regional spread in malignant sublingual gland tumour: Implications for surgical planning

Malignant tumours arising from the sublingual glands are very rare, and the extent and frequency of local invasion or regional spread in malignant sublingual gland tumour (MSLT) has not been fully studied due to the disease rarity. To provide comprehensive features of local and regional spread of MSLT, we reviewed 20 surgical cases for detailed pathological analyses among 26 cases diagnosed as having primary MSLT. Adenoid cystic carcinoma (ACC) was the most common pathological subtype, followed by mucoepidermoid carcinoma. Disease-free and overall survivals at 5 years were 76.1 % and 77.7 %, respectively. High-grade malignant tumours and grade 2-3 ACC accounted for 41.7 % and 85.7 %. Clinical and pathological extraparenchymal extensions were found in 34.6 % and 80.0 %, respectively. Tumour invasion to the lingual nerve and submandibular gland/ductal system were also detected in 40.0 % and 28.6 %. The incidences of lingual nerve invasion in ACC and ACC ≥4 cm were 30.8 % and 42.9 %. Regional nodal involvement occurred in seven of 26 cases, and all metastatic lymph nodes were found in neck levels Ib and IIa. In summary, a significant portion of MSLT cases consisted of high-grade tumours and grade 2-3 ACC; therefore local invasion into adjacent structures should be cautiously evaluated in cases of MSLT.

Secretory carcinoma of salivary glands at the National Cancer Institute: A 20-year retrospective clinical, pathological, immunohistochemical and molecular study

OBJECTIVES

This study aim was to review cases of acinic cell carcinoma (the main differential diagnosis of secretory carcinoma) that were diagnosed and treated at the National Cancer Institute of Brazil (INCA) between 1996 and 2016. The primary objective was to identify underdiagnosed cases of secretory carcinoma via a clinical, immunopathological and molecular reassessment.

MATERIALS AND METHODS

This is a cross sectional study, with retrospective data collection from medical records and histological specimen review, with staining for periodic acid-Schiff (PAS) and PAS with diastase, immunohistochemistry for S-100, mammaglobin, and DOG-1, and droplet digital RT-PCR for ETV6-NTRK3. The Research Ethics Committee approved this study, and the patients allowed their participation through informed consent.

RESULTS

Eighty-three cases of acinic cell carcinoma were diagnosed and treated in the specified period at INCA, of which, seven had their diagnosis changed to secretory carcinoma.

CONCLUSION

The present study adds seven cases of secretory carcinoma to the literature, contributing to a better understanding of the epidemiological, histological, immunohistochemical and molecular characteristics of this recently described tumor. Also, the use of a comprehensive diagnostic approach, including immunohistochemical and molecular methods, along with classical morphological studies, allowed the reclassification of acinic cell carcinoma to secretory carcinoma.

SS18 Break-Apart Fluorescence In Situ Hybridization is a Practical and Effective Method for Diagnosing Microsecretory Adenocarcinoma of Salivary Glands

Molecular analysis has allowed for refinement of salivary gland tumor classification and, in some cases, the recognition of entirely new tumor types. Microsecretory adenocarcinoma (MSA) is a salivary gland tumor described in 2019 characterized by microcystic growth, bland cytomorphology, luminal secretions, fibromyxoid stroma, and S100/p63 positivity with negative p40. Most important, MSA is defined by MEF2C-SS18 fusion. While this fusion has, to this point, been detected by next-generation sequencing, this is a technique that is currently inaccessible in most diagnostic laboratories. On the other hand, SS18 break-apart fluorescence in situ hybridization (FISH) is widely available and frequently used as an adjunct for diagnosing synovial sarcoma. It is not known if SS18 break-apart FISH is positive in tumors with MEF2C-SS18, or if it is entirely specific for MSA. Break apart FISH for SS18 was performed on 4 cases of MSA, as well as 8 tissue microarrays (TMAs) containing 423 various salivary gland carcinomas: 26 acinic cell carcinomas, 35 adenocarcinomas not otherwise specified, 96 adenoid cystic carcinomas, 3 basal cell adenocarcinomas, 20 epithelial-myoepithelial carcinomas, 15 hyalinizing clear cell carcinomas, 3 intraductal carcinomas, 12 myoepithelial carcinomas, 117 mucoepidermoid carcinomas, 30 polymorphous adenocarcinomas, 45 salivary duct carcinomas, 19 secretory carcinomas, and 2 undifferentiated carcinomas. SS18 break-apart FISH was also performed on whole slides of 2 tumors from the TMAs. All MSA cases demonstrated classic split patterns on SS18 break-apart FISH. On the TMAs, 374 cases were evaluable by FISH, and 372 cases were clearly negative for SS18 rearrangement. Two cases, both mucoepidermoid carcinomas, had rare split signals below the positivity threshold of 12% on their TMA cores, so FISH was performed on whole sections. On the whole sections both tumors were unequivocally negative for SS18 rearrangement. Taken together, SS18 break-apart FISH was 100% sensitive and 100% specific for a diagnosis of MSA. SS18 break-apart FISH, a diagnostic tool widely available in pathology laboratories, appears to be a highly accurate method for diagnosing MSA of salivary glands. Accordingly, this new tumor type may be molecularly confirmed without needing to resort to highly specialized techniques like next-generation sequencing.