Minor Salivary Gland Tumors Research Articles

The accuracy of fine needle aspiration cytology in the clinical diagnosis of minor salivary gland tumours

The objective of this study was to investigate the accuracy of fine needle aspiration cytology (FNAC) and biopsy for the clinical diagnosis of minor salivary gland tumours (MSGTs). This retrospective study of 32 MSGT cases was conducted over a 5-year period. Clinical features including age, sex, and location of the tumour were obtained from the patient clinical records. All cases were also assessed histologically according to the 2017 World Health Organization Classification of Head and Neck Tumours. The results of FNAC and biopsy were correlated with those of histopathology, and their sensitivity, specificity, and diagnostic efficacy were calculated using histopathology as the gold standard. Eighteen malignant MSGTs (56.3%) and 14 benign MSGTs (43.8%) were diagnosed by pathological diagnosis. The most common malignant tumour was mucoepidermoid carcinoma (seven cases, 38.9%). Most benign cases were pleomorphic adenomas (13 cases, 92.9%). FNAC was performed for 23 cases and biopsy for 13 cases. The sensitivity and specificity of FNAC were 66.7% and 91.0%, respectively, while those of biopsy were 90.0% and 100.0%, respectively. Although FNAC is a minimally invasive and cost-effective procedure, it is less accurate than biopsy in the assessment of MSGTs. Repeated FNAC or biopsy should be considered in negative and unsatisfactory FNAC cases.

Postoperative Management of Salivary Gland Tumors.

Salivary gland tumors represent a heterogeneous group of neoplasms characterized by varied histologies and disease outcomes. Initial treatment for the primary and gross nodal disease is usually surgery. Management of the clinically node-negative neck depends upon the risk of lymph nodal involvement. This is usually determined by the AJCC "T" stage and histology. Both surgery and radiation may be utilized to address the lymph nodes at risk. This is especially important for minor salivary gland tumors. Radiation plays an important role in the adjuvant management of salivary gland tumors by reducing the risk of locoregional recurrence. Certain histologies like adenoid cystic carcinoma have a predilection for neurotropic spread to the skull base. Radiation is particularly important in controlling disease at the skull base. The role of concurrent chemotherapy in the adjuvant treatment of salivary gland tumors is not established and remains an area of active research. Certain histologies like salivary duct carcinoma exhibit readily identifiable molecular targets amenable to targeted therapy. Finally, advanced testing of these tumors using next-generation sequencing can also potentially identify molecular targets amenable to therapy. While useful in the management of metastatic disease, the role of these therapies in the adjuvant setting remains unknown.

Immunohistochemical expression of OCT4 and CD44 in major and minor salivary gland neoplasms.

The aim of this study was to identify tumor parenchyma cells exhibiting immunohistochemical profile of stem cells by evaluating the immunoreactivity of OCT4 and CD44 in a number of cases of salivary gland neoplasms. The sample consisted of 20 pleomorphic adenomas, 20 mucoepidermoid carcinomas, and 20 adenoid cystic carcinomas located in major and minor salivary glands. The expression of OCT4 and CD44 was evaluated by the percentage of positive cells and the intensity of expression. All studied cases showed positive expression of OCT4 and CD44 and higher values than the control groups. For OCT4, luminal and non-luminal cells were immunostained in the case of pleomorphic adenomas and adenoid cystic carcinomas. Moreover, the immunoreactivity of CD44 was particularly evident in the non-luminal cells of these lesions. In mucoepidermoid carcinomas, there was immunoreactivity for both markers in squamous and intermediate cells and absence of staining in mucous cells. For both markers, a significantly higher immunostaining was verified in neoplasms located in the major salivary glands compared with lesions in minor salivary glands (p<0.001). In the total sample and in minor salivary glands, malignant neoplasms exhibited higher immunoreactivity for OCT4 than pleomorphic adenoma. A significant moderate positive correlation (r = 0.444 and p ≤ 0.001) was found between OCT4 and CD44 immunoexpression in the total sample. The high expression of OCT4 and CD44 may indicate that these proteins play an important role in identifying tumor stem cells.

Benign Salivary Gland Tumour Presenting as Unilateral Nasal Mass: Case Report of Pleomorphic Adenoma of Nasal Septum

Introduction: Unilateral nasal mass can be benign or malignant. Very rarely we will find benign salivary gland tumor in nasal cavity. Pleomorphic adenoma is still the most common pathological variety either in major or minor salivary gland tumors. In the nasal cavity, even though most of the accessory salivary glands are present in the lateral wall of nose, nasal septum remains the most common site of origin. Case Report: A 40-year-old female presented with right-sided nasal obstruction and epistaxis. CT scan of Nose and Paranasal sinuses found a lesion involving the anterior third of the right nasal cavity. The patient underwent complete surgical resection of the tumor via an endonasal approach. Histological examination found a mixed cellular component (epithelial and myoepithelial) and mesenchymatous tissue with chondromyxoid stroma, enabling diagnosis of a typical pleomorphic adenoma. Conclusion: Pleomorphic adenoma is the most common salivary gland tumor but rare to find in the nasal cavity with only few cases reported in the literature. Although benign, the risk of local recurrence, malignant transformation and metastasis requires close long-term follow-up.

Extensive squamous metaplasia in minor salivary gland neoplasm mimicking squamous cell carcinoma: Diagnostic dilemma in aspiration cytology

The surgical management of salivary gland lesions depends on cytology diagnosis, in conjunction with clinical findings and imaging studies. It is extremely important to differentiate benign and malignant salivary gland lesions preoperatively. The distinction can be challenging in aspiration cytology due to metaplastic changes, cystic changes, variable cellular components within the lesions, variants of neoplasms, and sampling issues. We are presenting the case of a 42-year-old female patient who presented with a nodular lesion in the hard palate. Fine-needle aspiration cytology of the lesion was cellular and showed sheets and singly scattered squamous cells with minimal cytological atypia. As the differential diagnosis included variety of lesions ranging from nonneoplastic lesions to benign and malignant neoplasms, surgery under frozen section control was advised. Frozen sections also showed extensive squamous areas. A minor component showing bilayered ductal pattern in a background of chondromyxoid stroma also noted. Diagnosis of a salivary gland neoplasm, possibly pleomorphic adenoma with extensive squamous metaplasia was given. Although squamous metaplasia has been reported in salivary gland neoplasms, it is extremely rare to find extensive squamous metaplasia enough to cause significant diagnostic confusion. The awareness of this extensive squamous metaplasia in benign salivary gland lesions help to distinguish it from malignant lesions and to avoid unnecessarily aggressive therapy.

Imaging of Malignant Minor Salivary Gland Tumors of the Head and Neck.

Minor salivary gland carcinomas (MSGCs) are nonminor tumors in the head and neck region and account for about half of all salivary gland carcinomas. Imaging evaluation based on the anatomy of minor salivary and mucous glands in the head and neck region as well as invasion patterns in each site helps in identifying optimal treatment modalities and planning suitable treatment strategies. MSGCs can be divided radiologically into localized and invasive subtypes on the basis of the clinical utility of such categorization. Characteristic invasion patterns of the invasive type include deep submucosal extension, bone marrow infiltration, and perineural spread, which are difficult to assess clinically. MSGCs easily invade adjacent structures because of their submucosal location and may spread along the muscles, nerves, periosteum, and dura mater. Moreover, the tumor may spread into the bone marrow without obvious bone destruction. In addition to imaging classification, examining the anatomy and distribution of the minor salivary glands, including the palatal, lingual, buccal, labial, and retromolar glands, as well as other mucous glands, including the glands of the sinonasal cavity and nasopharynx, lacrimal glands, ceruminous glands, laryngeal glands, and tracheal glands, facilitates MSGC diagnosis and tumor extension assessment. The authors review the precise anatomy of the minor salivary and mucous glands in the head and neck region, discuss the MSGC imaging classifications, and describe how to evaluate the extent of MSGCs in each site on the basis of the imaging classification and invasion patterns. ©RSNA, 2020.

Salivary gland tumours: a hospital-based study on demographic and incidence pattern, histopathological types and treatment strategy

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;Salivary gland tumours constitute 3-4% of all head and neck cancers (mostly benign). These tumours are epithelial (95%) or mesenchymal in origin. Pleomorphic adenoma is the most common benign salivary gland tumour and mucoepidermoid carcinoma (45%) is the most common malignant salivary gland tumour followed by adenoid cystic carcinoma (30%). The parotid, submandibular and the minor salivary glands of palate are commonly involved and the sublingual gland is rarely affected.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;Hospital based cross sectional study was done in a tertiary care centre during a period of 1 year, which included 21 patients (10 men and 11 women). Patients were analysed according to age, gender, food habits, histopathological type and site of the tumour and treatment strategy.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;All the cases were from upper Assam province sharing a particular demographic pattern between 19-65 years. Peak incidence in males was fourth decade and females was third decade. Male female ratio was 0.9:1. Out of 21 cases, 14 were parotid gland tumours, 6 submandibular gland tumours and 1 minor salivary gland tumour. Most of the tumours were benign (16) and 5 were malignant.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Two patients were of age 19 years which is conflicting the normal national incidence. All cases belonged to lower economic strata with decreased intake of beta carotene enriched food items. The most common site is parotid gland and most common tumour is pleomorphic adenoma which is in accordance to other studies. Benign cases were subjected to superficial parotidectomy and malignant cases to total parotidectomy with neck dissection.&lt;/p&gt;

Salivary gland tumours in Iceland 1986-2015: a nationwide epidemiological analysis over a 30-year time period.

Salivary gland tumours (SGT) are a vast and heterogenous group of neoplasms. There is a relative lack of comprehensive nationwide epidemiological studies on the subject. The aim of this nationwide analysis was to gain insight into epidemiological traits, such as site, incidence and histological subtypes of SGT in general. Patients diagnosed with a primary SGT between 1986 and 2015 were identified from The Icelandic Cancer Registry and registries from all pathology departments in Iceland. Information on age, sex, tumour location and histology was retrieved from pathology reports. A total of 687 patients were diagnosed with a SGT, 609 (89%) were benign and 78 (11%) malignant. 9% of parotid gland tumours, 22% of submandibular gland tumours and 26% of minor SGT were malignant. The most common malignant tumours were mucoepidermoid carcinoma, acinic cell carcinoma and adenoid cystic carcinoma. The incidence of benign SGT was 4.9 per 100000 among men and 7.0 per 100000 among women. The incidence of malignant tumours was 0.59 per 100000 for men and 0.79 per 100000 for women. The proportion of malignant SGT is lower than most often reported. Only 10% of parotid gland tumours, 20% of submandibular gland tumours and 25% of minor salivary gland tumours are malignant.

Clinicopathological and Incidence Analysis of Malignant Salivary Gland Tumours: A 16-year Retrospective Study in the North of Portugal

Objectives: A) Evaluate the clinical-pathological characteristics of malignant neoplasms of salivary glands: A.1) Quantify the numbers of which tumor subtype. A.2) Gender, age and the type of salivary gland influence tumor behavior? A.3) Describe 16 years of evolution in a target portuguese population. B) What are the treatments chosen in which subtype? C) What is the prognosis? And what can influence the prognosis? Study Design: A 16-year retrospective study of 138 patients with salivary gland tumors from 2000 to 2016 in the Anatomical Pathology Department of Centro Hospitalar do Porto, Hospital Geral de Santo António. The histological diagnoses - according to the 2017 World Health Organization classification. Results: In the present study, we revised all the cases of salivary gland pathology from 396 cases. A total of 138 tumors were identified in 91 male and 47 female patients. The mean age was 58 years. The frequency of major salivary gland tumors was 56.3%, and that of minor salivary gland tumors was 43.7%. Mucoepidermoid carcinoma was the most common malignant tumor. Conclusions: Knowledge of the different clinic characteristics is important and essential to a better prognosis and in many cases a reduction of the mortality.

Lipomas: A Case Series

Aim: This report aims to present 5 cases of intraoral lipoma with clinical findings, surgical treatment and histopathological features. Case Report: Provisional diagnosis of minor salivary gland neoplasm, fibroma and lipoma was made for all of the cases according to clinical examination. Excisional biopsy was performed with blunt dissection. Lobular, yellowish, encapsulated masses were obtained from the patients and excised specimens were sent to pathology laboratory for histopathological analysis. Results: After histopathological examination, all cases were diagnosed with simple lipoma. Successful healing of the oral mucosa was observed in postoperative period. Conclusion: The most important feature of these tumours is that they are asymptomatic. Differential diagnosis is important as it includes malign tumours and some genetic diseases that may be related to tumour. Key Words: Lipoma, Oral Surgery Intraoral Lipom: Vaka Serisi Öz Amaç: Bu çalışmada 5 intraoral lipom olgusunun klinik bulguları, cerrahi tedavisi ve histopatolojik özellikleri sunulmaktadır. Olgu Sunumu: Tüm olgularda klinik muayene sonrasında minör tükürük bezi neoplazmı, fibrom ve lipom tanısı düşünülmüştür. Vakaların eksizyonel biyopsileri künt diseksiyon ile yapılmıştır. Eksize edilen örnekler lobüler, sarımsı, kapsül ile çevrili kitleler olarak gözlemlenmiştir ve histopatolojik analiz için patoloji laboratuvarına gönderilmiştir. Bulgular: Histopatolojik inceleme sonrasında tüm olgulara basit lipom tanısı konulmuştur. Postoperatif dönemde oral mukozanın başarılı şekilde iyileştiği görülmüştür. Sonuç: Bu tümörlerin en önemli özelliği, asemptomatik olmalarıdır. Ayırıcı tanı, malign tümörleri ve tümörle ilişkili olabilecek bazı genetik hastalıkları içermesi sebebiyle önemlidir. Anahtar Kelimeler: Lipom, Oral Cerrahi

EPIDEMIOLOGIC ANALYSIS OF SALIVARY GLAND TUMORS OVER A 10-YEAR PERIOD DIAGNOSED IN A NORTHEAST BRAZILIAN POPULATION

Objective: To analyze the clinical profile of a series of salivary gland tumors diagnosed in the state of Sergipe. Study Design: This is an epidemiologic, analytical, and retrospective study of the clinical characteristics of salivary gland tumors, carried out in medical/oral pathology reference services in the state of Sergipe. The cases were collected in the laboratories database. All cases of major and minor salivary gland tumors that met the diagnostic criteria established by the World Health Organization (WHO) and diagnosed between 2006 and 2016 were selected. Cases were diagnosed by fine needle aspiration; inconclusive reports and secondary tumors were excluded. Results: A total of 588 cases were found. The majority of tumors occurred in women (55.7%), ranging from 41 to 50 years of age (19.06%). Benign tumors were more common (79.5%), and major salivary glands were more affected (61.73%), particularly the parotid gland (51.7%). Pleomorphic adenoma (88.96%) and Warthin tumor (6.8%) were the most common benign tumors, whereas mucoepidermoid carcinoma (24.58%), not otherwise specified adenocarcinoma (20.34%), and adenoid cystic carcinoma (17.8%) were the most frequent malignant tumors. Conclusions: Pleomorphic adenoma and mucoepidermoid carcinoma were the most common benign and malignant salivary gland tumors, respectively, and the parotid gland was the most affected anatomic site.

DEMOGRAPHIC PROFILE OF SALIVARY GLAND TUMORS IN THE BRAZILIAN POPULATION: A MULTICENTER STUDY

Objective. To determine the demographic profile of salivary gland tumors histologically diagnosed in the Brazilian population. Study design. A retrospective multicenter study from 3 different centers of oral diagnosis was conducted. Demographic data and histopathological diagnosis of salivary glands tumors over a 60-year period were evaluated. Data were analyzed descriptively. Results. Among 72,554 oral biopsies from all services, 774 (1.07%) were histologically diagnosed as salivary gland tumor, with 460 cases of benign tumor (59.43%). Most patients were women (446; 60.21%) and the majority of cases were distributed in the sixth decade of life (139; 17.96%) with a mean age ± standard deviation (SD) of 45.73 ± 18.50 years. The palate was the most affected site (413; 53.36%). The most frequent tumors were pleomorphic adenoma (410; 40.4%), mucoepidermoid carcinoma (99; 9.8%), and adenoid cystic carcinoma (64; 6.3%). Pleomorphic adenoma was frequent in patients younger than 47 years of age and the most affected site was the palate (P = .002 and P = .003, respectively). Mucoepidermoid carcinoma was more frequent in women than men (P = .002). Conclusion. Our results showed demographic aspects and clinical characteristics of minor salivary glands tumors, and these could be used as baseline data to obtain more epidemiologic information about these tumors especially in the Brazilian population. Objective. To determine the demographic profile of salivary gland tumors histologically diagnosed in the Brazilian population. Study design. A retrospective multicenter study from 3 different centers of oral diagnosis was conducted. Demographic data and histopathological diagnosis of salivary glands tumors over a 60-year period were evaluated. Data were analyzed descriptively. Results. Among 72,554 oral biopsies from all services, 774 (1.07%) were histologically diagnosed as salivary gland tumor, with 460 cases of benign tumor (59.43%). Most patients were women (446; 60.21%) and the majority of cases were distributed in the sixth decade of life (139; 17.96%) with a mean age ± standard deviation (SD) of 45.73 ± 18.50 years. The palate was the most affected site (413; 53.36%). The most frequent tumors were pleomorphic adenoma (410; 40.4%), mucoepidermoid carcinoma (99; 9.8%), and adenoid cystic carcinoma (64; 6.3%). Pleomorphic adenoma was frequent in patients younger than 47 years of age and the most affected site was the palate (P = .002 and P = .003, respectively). Mucoepidermoid carcinoma was more frequent in women than men (P = .002). Conclusion. Our results showed demographic aspects and clinical characteristics of minor salivary glands tumors, and these could be used as baseline data to obtain more epidemiologic information about these tumors especially in the Brazilian population.

Pleomorphic Adenoma of Palate – A Case Report and Review of Literature

10% of pleomorphic adenomas occur in the minor salivary glands with the palate being the most common site. Pleomorphic adenomas account for the majority of palatal tumours; however, minor salivary gland tumours have a higher risk of malignancy compared to tumours of the major salivary glands, so definite diagnostic evaluation should be executed. A case of 26-year-old man with a longstanding history of a soft palate pleomorphic adenoma which required excision under general anaesthetia We discuss the appropriate preoperative investigations, operative technique for surgical excision, histopathologic interpretation for this patient and brief review of literature for pleomorphic adenoma.

PARTIAL AIRWAY OBSTRUCTION IN AN ASYMPTOMATIC PATIENT

<h3>Background</h3> A 66-year-old female with no complaints or symptoms presented for routine preimplantation cone beam computed tomography (CBCT). CBCT demonstrated evidence of a large, well-defined, low-attenuation/soft tissue lesion with an undulating appearance, extending from the posterior left pharyngeal wall and occluding two-thirds of the airway from the level of C2 to C4. The lesion extended laterally into the left mediopharyngeal space and inferiorly beyond the field of view. There was evidence of faint internal septations. <h3>Objective</h3> The aim of this study was to identify, diagnose, and treat a large lesion partially obstructing the airway through multiple advanced imaging modalities and interdisciplinary collaborative treatment. <h3>Materials and Methods</h3> The patient was referred for an otolaryngology consult after initial CBCT imaging. Laryngoscopy, magnetic resonance imaging (MRI) and contrast-enhanced computed tomography (CT) were performed to determine the extent of the lesion and to plan for potential surgical intervention. <h3>Results</h3> The absence of symptoms and displacement of surrounding structures without perforation suggested a benign, but fairly invasive, neoplasm with slow growth. Initial differential diagnoses included lipoma, minor salivary gland tumor, and vascular and neural tumors. Juxtaposition of T1-weighted MRI and T1 with fat suppression protocols further validated the diagnosis of benign lipoma. Resection, followed by histopathologic evaluation, confirmed a large lipoma. Periodic follow-up was recommended to monitor resolution and potential recurrence. <h3>Discussion</h3> Lipomas account for 4% to 5% of benign neoplasms, more commonly in the lower torso and extremities. Lipomas in the upper airway region account for only 0.6% of benign neoplasms, making them quite rare. Any lesion encroaching on vital structures needs prompt attention and appropriate intervention/management to avoid a life-threatening situation. The slower growth exhibited by some benign lesions may obscure symptoms because the changes are gradual and happen over an extended period. Incidental findings, such as this large and invasive benign tumor, underscore the importance of carefully evaluating the entire volume of any study and not just the region of interest.

Major and minor salivary gland tumours.

Salivary glands carcinomas are very rare epithelial malignant tumors. In 2013 in Europe, 7800 new diagnoses were estimated, 8.5 % of all head and neck cancer. The last WHO classification (2017) counts more than 20 malignant histotypes, this variety as well as the rarity of some of them needs a skilled pathologist for diagnosis. Surgery remains the mainstay of management followed by radiation in high-grade and high-risk pathological features cases. The intensity modulated radiotherapy (IMRT) should be preferred over conformational radiotherapy techniques as adjuvant and exclusive treatment in advanced cases. Particle radiotherapy (i.e. protons, carbon ions) can have a role in advanced/unresectable disease since it was proved to have better results over photons in loco-regional control both in adenoid cystic carcinoma and in other histotypes. Although chemotherapy is still the most frequent treatment for metastatic patients, several new compounds (i.e. anti-angiogenic agents, tailored agents, checkpoint inhibitors) are under investigation.

Clinicopathological profile of adenoid cystic carcinoma of minor salivary gland tumour: our experience at a tertiary care centre

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Adenoid cystic carcinoma (ACC) is a rare malignant tumour originating from minor salivary glands. It is known for perineural spread, local recurrences and distant metastasis. The minor salivary gland tumour represents 3% of all head and neck neoplasms, whereas ACC constitutes about 0.5% of all malignant salivary gland neoplasms. This study was done to evaluate the clinical presentation and histopathological findings of minor salivary gland tumour.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This study was done in the department of ENT, Bangalore Medical College and Research Institute from May 2017 to July 2019. Of the 25 patients with minor salivary gland tumour, 10 patients with ACC were considered for the present study. A detailed clinical and histopathological evaluation was done. Results were documented and tabulated in excel sheet. &lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; We analysed data of 25 (16 female, 9 male) patients in the age group of 30-60 years, of which 10 patients had adenoid cystic carcinoma of minor salivary gland tumour. The most frequent site of tumour occurrence was noted in the hard palate (6 patients), followed by retromolar trigone (2 patients), floor of mouth (1 patient) and tongue (1 patient). The histopathological pattern noted most commonly in our study: cribriform pattern (6 cases), tubular (1 case) and solid (3 cases).&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; ACC of minor salivary glands is rare. The otorhinolaryngologist should bear this clinical entity in mind when encountered with a painless swelling over the hard palate. This would lead to an early diagnosis and prompt management in such patients.&lt;/p&gt;

Usual pathology at an unusual site - pleomorphic adenoma of parapharyngeal space: a rare case report

&lt;p class="abstract"&gt;The parapharyngeal space is an inverted triangular pyramid. Parapharyngeal space masses account for 0.5% of all head and neck tumours and the majority is benign. Minor salivary gland tumour is a rare entity. A 75 years old female presented with a mass left side soft palate, per operatively mass of size about 6×3 cm was deeply extending to left parapharyngeal space and excised through transoral approach which came out to be pleomorphic adenoma of minor salivary gland on histopathological examination. Although external approach should be preferred due to important structure in vicinity but transoral approach can be used in selective cases.&lt;/p&gt;

Novel Approach for Management of Extremely Rare Pleomorphic Adenoma of Soft Palate (Minor Salivary Glands).

Salivary gland tumours account for 2-3% of tumours occurring in head and neck region, majority of them being benign. Pleomorphic Adenoma present mainly in Parotid gland and Sub-mandibular gland and rarely in minor salivary glands. The tumours of minor salivary glands are generally malignant. The commonest sites of intra oral Pleomorphic adenoma are palate, lip and buccal mucosa. Here I describe a very rare case of Pleomorphic Adenoma in minor salivary glands and its novel management using CO2 Laser. There was no recurrence seen after a follow-up period of around one year.

Prevalence of mucoepidermoid carcinoma among intraoral minor salivary gland tumors: A systematic review and meta-analysis.

This study aimed to synthetize and critically appraise available evidence regarding mucoepidermoid carcinoma (MEC) prevalence among intraoral minor salivary gland tumors (MiSGT). Five main electronic databases and three grey literature databases were searched. The risk of bias (RoB) was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data. Proportion meta-analyses were performed. From 1321 studies identified, 82 were included in qualitative synthesis and 80 in meta-analyses. Sixteen were classified as high, 33 as moderate, and 33 as low RoB. A total of 12774 MiSGT were found, of which overall MEC prevalence was 16.5% (95% Confidence Interval [95% CI]=14.8%-18.4%). Most MiSGT were found in the palate (n=7115), although MEC pooled prevalence in this anatomic location was only 13.6% (95% CI=11.7%-15.6%). The retromolar area presented the highest pooled prevalence (58.9%; 95% CI=47.0%-70.3%), followed by gingiva (28.8%; 95% CI=22.7%-35.4%) and tongue (27.2%; 95% CI=21.2%-33.6%). Regarding geographic location, Middle East presented the highest pooled prevalence (20.8%; 95% CI=14.8%-27.6%), followed by America (20.0%, 95% CI=17.2%-23%) and Europe (15.6%; 95% CI=9.2%-23.5%). Among MiSGT, the MEC overall prevalence was approximately 16.5%. Although most MiSGT were found in the palate, the retromolar area was proportionally more affected by MEC.

Human Tissue Kallikreins in Polymorphous Adenocarcinoma: A Polymerase Chain Reaction and Immunohistochemical Study.

Polymorphous adenocarcinoma (PAC) is the second most common malignant salivary gland tumour of minor salivary glands. Human tissue kallikreins (KLKs) are a family of highly conserved serine proteases expressed by various tissues and organs. The literature demonstrates a link between KLKs and salivary gland neoplasms. The purpose of this study was to determine levels of KLK mRNA in tissue samples of PAC and to determine if KLK expression is limited to tumour cells. Nineteen cases of PAC were reviewed (1987-2013). The diagnosis was confirmed, demographic data was collected, and formalin fixed paraffin-embedded PAC and normal salivary gland tissue samples were obtained. RNA isolation was achieved, followed by conversion to complementary DNA via reverse transcription. Using PCR, the quantitative level of expression of KLKs1-15 was recorded. Samples exhibiting high and low KLK expression were selected for immunohistochemistry staining. Results revealed a statistically significant increase in mean KLK mRNA expression for KLK1, KLK4, KLK10, KLK12 and KLK15 in PAC tissue samples, compared with normal salivary gland tissue (Mann-Whitney U test, p < 0.05). Immunohistochemistry results demonstrated that KLKs were present in tumor cells. Notably, all samples demonstrating relatively higher KLK mRNA expression showed equivalent or increased staining scores relative to the low KLK mRNA expression samples. In conclusion, there appears to be aberrant kallikrein expression in polymorphous adenocarcinoma, suggesting the possibility of a kallikrein cascade influence on tumor development and progression.