The frequency and distribution pattern of minor salivary gland tumors in a government dental teaching hospital, Chennai, India

Salivary gland tumors: an audit from a tertiary care centre in Northern India

Salivary gland tumors are relatively rare and can exhibit various clinical behaviors. The study aims to understand the natural history, pathology, diagnostic workup, and treatment strategies for these tumors to improve patient outcomes. The audit included patients with salivary gland tumors detected through radiology or cytology. Patients underwent surgery, with some receiving adjuvant treatment. Demographic information, treatment interventions, and survival outcomes were analyzed using SPSS software. A total 89 as malignant salivart gland tumours were audited Malignant tumors were predominantly found in the parotid gland, with fewer cases in the minor salivary gland and submandibular gland.The median age of presentation was 47 years, and the majority of patients were male. The study examined various pathological and clinical factors, including tumor stage, nodal status, and the presence of facial palsy. Surgical procedures and histological types of tumors were documented. Adverse histological features like positive margins, lymph node positivity, lympho-vascular invasion, extracapsular spread, and perineural invasion were noted. POSTOP RT was administered to high-risk patients. Most malignant salivary gland tumors were found in the parotid gland, while minor salivary gland tumors were underrepresented in the audit. Surgical practices were diverse. Radiotherapy protocols were relatively standardized. The study found that certain histological features, such as lymph node positivity, margin positivity, lympho-vascular invasion, perineural invasion, and extracapsular spread, were associated with adverse effects on DFS and OS. The findings suggest that specific histological features, including LVI and ECE have emerged as independent prognostic factors for DFS and OS.

Intraoral Minor Salivary Gland Tumors: A Retrospective, Clinicopathologic, Single-Center Study of 432 Cases in Japan and a Comparison with Epidemiological Data

BACKGROUND

Intraoral minor salivary gland tumors are relatively rare lesions with histological subtypes not commonly found in major salivary glands. This study aimed to retrospectively evaluate the clinicopathologic features of intraoral minor salivary gland tumors from the Tokyo Dental College Hospital, Japan, and compare them with findings from other epidemiological studies.

METHODS

We conducted a retrospective clinicopathologic evaluation of 432 cases of intraoral minor salivary gland tumors [161 male (37.3%) and 271 female (62.7%) patients; mean age: 52.5 and 48.6 years for males and females, respectively; age at diagnosis: 7-87 (mean: 50.1) years] from the Tokyo Dental College Hospital between 1975 and 2022, including 283 benign tumors (65.5%) and 149 malignant tumors (34.5%).

RESULTS

The most common benign tumor was pleomorphic adenoma (n = 239), whereas mucoepidermoid carcinoma was the most common malignant tumor (n = 74). The mean age of patients with benign and malignant tumors was 48.4 and 53.2 years, respectively, with patients with malignant tumors being significantly older (P = 0.0042). The mean age of patients with malignant tumors was significantly higher in males (56.7 years) than in females (50.9 years) (P = 0.0376), although the mean age of patients with benign tumors did not differ by sex. Tumors were commonly located in the palate [250 cases (57.9%)]. Benign tumors were more frequent in the palate, upper lip, and buccal mucosa, whereas malignant tumors were more frequent in the palate, floor of the mouth, buccal mucosa, and retromolar area.

CONCLUSIONS

Understanding the features of intraoral minor salivary gland tumors is useful for diagnosis. Our study provides important epidemiological data (patient differences in age at occurrence, sex, and site of origin) that will inform clinicians and researchers.

The Evaluation and Management of Carcinoma of the Minor Salivary Glands

There are several hundred minor salivary glands throughout the upper aerodigestive tract, aiding in lubrication and protection of the system. Compared with all tumors of the head and neck and those of the six major glands, neoplasms of the minor glands are rare. However, more than half are found to be malignant, prompting a low threshold for further work-up. This review discusses the evaluation of patients who present with masses of the minor salivary glands, including strategies for tissue diagnosis and staging. Management options for and long-term survival outcomes of the most common malignancies affecting these glands are also discussed.

Why is the histomorphological diagnosis of tumours of minor salivary glands much more difficult?

AIMS

There is a widespread perception among clinicians and pathologists that the histomorphological assessment of minor salivary gland (MinSG) tumours is more difficult and hampered by more misdiagnoses than that of major salivary gland tumours. This is based on a vague, subjective clinical impression, lacking scientific proof. The aim of the present study was to identify and statistically verify potential reasons that could explain this difference.

METHODS AND RESULTS

We identified 14 putative clinical, pathological and combined clinicopathological reasons that, altogether, could explain the phenomenon of the perceived greater diagnostic difficulty associated with MinSG tumours. We performed a comprehensive literature search and a statistical comparison of data from a large personal consultation series (biased for difficult cases) with cumulated data from straightforward, unselected (non-consultation) series from the literature. By performing this comparison, we identified, with statistical significance, a comprehensive series of reasons, as well as of consequences, of the greater difficulty in diagnosing MinSG tumours.

CONCLUSIONS

Among the 14 criteria, high frequencies of initial incisional biopsies and of a low-grade category in malignant tumours emerged as the two most important reasons for enhanced diagnostic difficulty. Very rare entities, unusual locations, shortcomings in clinicopathological communication, and pecularities of the special anatomical location of the hard palate, such as tumour necrosis, mucosal ulceration, pseudoinvasion, and the peculiar phenomenon of 'tumoral-mucosal fusion', contribute to further diagnostic difficulties. The awareness of these shortcomings and pitfalls enables us to provide a series of recommendations for clinicians and pathologists that might aid in assessment and reduce the rate of misdiagnosis of MinSG tumours.

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 12 774 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.

Navigating small biopsies of salivary gland tumors: a pattern-based approach

Diagnosis of salivary gland tumors on small biopsy can be difficult because of overlapping morphology, limited tissue availability, and technical artifact. Although a specific diagnosis is not feasible in all cases, a cautious and thoughtful approach to the differential diagnosis and a keen awareness of clinical consequences can facilitate the most complete and useful classification possible. In this review, we present a general strategy for the evaluation of small salivary biopsies, including consideration of clinical and radiographic information, systematic assessment of histologic patterns, and judicious use of immunohistochemistry and molecular studies. We then focus on the distinctive differential diagnoses raised by 6 specific histologic patterns: tubular and cribriform architecture, squamous differentiation, mucin and other secretions, high-grade cytology, epithelial and lymphoid elements, and oncocytic features. Throughout this systematic and pattern-based approach, we focus on practical and cost-effective strategies to overcome the most common diagnostic challenges in limited material.

Oridonin induces the apoptosis of mucoepidermoid carcinoma cell lines in a myeloid cell leukemia‑1‑dependent manner

Oridonin, an active diterpenoid isolated from Rabdosia rubescens, has been reported to exhibit anticancer activities in several tumors. The aim of the present study was to investigate the anticancer effects and molecular mechanisms of oridonin in mucoepidermoid carcinoma (MEC). Treatment with oridonin induced the apoptosis of MC‑3 and YD‑15 cell and inhibited the expression of myeloid cell leukemia‑1 (MCL‑1) through the regulation of the protein level through post‑translational regulation in these cell lines. Oridonin significantly increased the expression level of truncated Bid (t‑Bid) as a downstream target of MCL‑1 and subsequently decreased the mitochondrial membrane potential. The ectopic expression of MCL‑1 protein was sufficient to reverse the induction of apoptosis and the increased t‑Bid expression induced by oridonin in both cell lines. Taken together, these results suggest that oridonin exerts an apoptotic effect through the modulation of MCL‑1 and t‑Bid in human MEC cell lines and may thus be a potential anticancer drug candidate for the treatment of human MEC.

Challenges in Minor Salivary Gland Biopsies: A Practical Approach to Problematic Histologic Patterns

Evaluation of minor salivary gland biopsy can be fraught with a wide range of problems, including technical limitations due to the small size and distorted nature of tissue received and interpretive difficulties navigating the considerable morphologic and immunohistochemical overlap between widely disparate entities. As such, common pathologic findings can evoke a perplexing differential diagnosis that encompasses malignant, benign, and non-neoplastic processes. This review will present the diagnostic considerations that arise from four histologic patterns that are frequently encountered on minor salivary gland biopsies: squamous differentiation, tubular and cribriform growth, mucin production, and myxoid stroma. The discussion herein will emphasize practical strategies and priorities for navigating these differential diagnoses in a clinically-relevant and cost-effective manner.

Minor intraoral salivary gland tumors: a clinical-pathological study

Objective

To evaluate the clinical-pathological profile of patients with minor salivary gland neoplasms.

Methods

A retrospective study of specific cases diagnosed as benign and malignant tumors of the minor salivary glands was performed. The data were collected from medical records of patients seen at a hospital over a period of 15 years. The sample was made up of 37 cases. For the pathological study, slides containing 5μm thick sections stained with hematoxylin and eosin were used. The data were tabulated using descriptive statistics.

Results

Malignant neoplasms represented 70.3% of cases. The mucoepidermoid carcinoma was the most common neoplasm (45.9%), followed by pleomorphic adenoma (24.4%). Most patients were female (70.3%), aged between 71 and 80 years. The palate (67.6%) and the retromolar region (10.8%) were the most affected sites.

Conclusion

Mucoepidermoid carcinoma was the most common tumor in minor salivary glands. These tumors are more common in females aged over 40 years. The palate was the most common affected site.

Objetivo

Avaliar o perfil clínico-patológico de pacientes com neoplasias de glândula salivar menor.

Métodos

Foi realizado um estudo retrospectivo de casos específicos diagnosticados como neoplasias benignas ou malignas de glândula salivar menor. Os dados foram coletados dos prontuários dos pacientes atendidos em um hospital no período de 15 anos. A amostra final foi de 37 casos. Para o estudo histopatológico, foram usadas lâminas contendo secções com 5μm de espessura, coradas pela técnica de hematoxilina e eosina. Os dados foram tabulados de forma descritiva.

Resultados

As neoplasias malignas representaram 70,3% dos casos. O tipo histológico mais prevalente foi o carcinoma mucoepidermoide (45,9%), seguido do adenoma pleomórfico (24,4%). A maioria dos pacientes era do sexo feminino (70,3%), com idade entre 71 e 80 anos. O palato (67,6%) e a região retromolar (10,8%) foram os sítios mais acometidos.

Conclusão

O carcinoma mucoepidermoide foi o tumor mais comum das glândulas salivares menores. Estes tumores foram mais comuns em mulheres com mais de 40 anos. O palato foi o sítio mais acometido.

Immunoexpression of GLUT-1 and angiogenic index in pleomorphic adenomas, adenoid cystic carcinomas, and mucoepidermoid carcinomas of the salivary glands

This study aimed to evaluate and compare the immunoexpression of glucose transporter-1 (GLUT-1) and angiogenic index between pleomorphic adenomas (PAs), adenoid cystic carcinomas (ACCs), and mucoepidermoid carcinomas (MECs) of the salivary glands, and establish associations with the respective subtype/histological grade. Twenty PAs, 20 ACCs, and 10 MECs were submitted to morphological and immunohistochemical analysis. GLUT-1 expression was semi-quantitatively evaluated and angiogenic index was assessed by microvessel counts using anti-CD34 antibody. Higher GLUT-1 immunoexpression was observed in the MECs compared to PAs and ACCs (p = 0.022). Mean number of microvessels was 66.5 in MECs, 40.4 in PAs, and 21.2 in ACCs (p < 0.001). GLUT-1 expression and angiogenic index showed no significant correlation in the tumors studied. Results suggest that differences in biological behavior of the studied tumors are related to GLUT-1. Benign and malignant salivary gland tumors differ in the angiogenic index; however, angiogenesis may be independent of the tumor cell's metabolic demand.

Histopathological spectrum of polymorphous low-grade adenocarcinoma

Polymorphous low-grade adenocarcinomas (PLGA) are distinctive salivary gland neoplasms, with an almost exclusive propensity to arise from the minor salivary glands. PLGA frequently manifests as an asymptomatic, slow-growing mass within the oral cavity, which must be separated from adenoid cystic carcinoma and benign mixed tumor for therapeutic and prognostic considerations. We report a case of a 67-year-old male, who presented with a long-standing mass in the palate. This lesion was diagnosed as PLGA based on histopathological findings, which was further confirmed by the immunohistochemical marker.

Polymorphous low-grade adenocarcinoma of the upper lip: 11 cases of an uncommon diagnosis

OBJECTIVE

The aim of this case study was to describe an international case series of polymorphous low-grade adenocarcinoma (PLGA) affecting the upper lip.

MATERIAL AND METHODS

Over a 30-year-period, the files of five pathology services were reviewed for PLGA affecting the upper lip. Hematoxylin and eosin-stained slides were reviewed by three oral and maxillofacial pathologists, and microscopic features were described. Clinical data were retrieved from patients' medical records.

RESULTS

The review identified 11 cases of upper lip PLGAs, with a complete set of clinical data available for 5 cases. There was a male predominance (1.2:1), and the mean age was 58.7 years. Most cases presented as small asymptomatic swellings that resembled benign tumors. All patients underwent surgery, and no recurrences or metastases were reported in the 8 cases from which follow-up data were available. Microscopically, the typical polymorphic architectural arrangement of PLGA was seen in all cases, with lobular, trabecular, papillary, and cribriform patterns identified. Perineural invasion, normal gland entrapment, Indian filing, and concentric growth were frequently identified.

CONCLUSION

PLGA must be included in the list of differential diagnoses of tumors affecting the upper lip because of its similar clinical presentation to benign entities. The follow-up data available from 8 of 11 cases suggest that these tumors follow a low-grade clinical course, similar to the majority of palatal cases of PLGA.

Primary lymphoepithelial carcinoma of the intraoral minor salivary gland: A case report

Lymphoepithelial carcinoma (LEC) of salivary gland origin is a rare malignant tumor with morphological characteristics identical to those of undifferentiated nasopharyngeal carcinoma. It has a marked racial predilection for Inuit and Southeast Asian populations. An association between LEC and Epstein-Barr virus (EBV) infection has previously been reported. LEC most frequently affects the parotid gland, followed by the submandibular glands. To the best of our knowledge, only three LECs arising from the minor salivary gland have been previously described in the English language literature. The current study reports a case of EBV-associated LEC of the minor salivary gland in the hard palate of a 38-year-old Chinese female, and reviews the clinicopathological characteristics of this uncommon tumor.

Polymorphous low-grade adenocarcinoma: a case series and determination of recurrence

OBJECTIVES/HYPOTHESIS

Information on polymorphous low-grade adenocarcinoma (PLGA) consists primarily of case reports and small institutional series with varying recurrence rates. In this report, we describe our institutional experience and conduct a review of the literature to assess the overall incidence of PLGA among oral salivary gland tumors and determine recurrence rates.

STUDY DESIGN

A retrospective case series and literature-based review was performed.

METHODS

Retrospective case series at an academic tertiary referral center. Review of clinical records and pathological analysis of tissue specimens from 20 patients treated for PLGA from July 1, 1990 to July 1, 2011. A literature-based review on PLGA was also performed.

RESULTS

Twenty patients (mean age, 54 years; eight males) with PLGA based on pathologic diagnosis were included. The most common initial presentation was an asymptomatic mass (45%), and the most frequent site was the palate (60%). Our literature review identified 54 case reports, eight case series, and 17 large series. In total, 456 cases of PLGA were identified, with an overall recurrence rate of 19%. Half of the recurrences occurred by 36 months; however, recurrences were reported up to 24 years after initial resection.

CONCLUSIONS

PLGA arises from minor salivary glands and is characteristically slow growing and indolent. Although these tumors may be histologically low-grade, our review highlights the high rates of recurrence of these tumors as well as the ability to metastasize to local lymph nodes and distant organs. The mainstay of treatment should be wide surgical excision with long-term oncologic follow-up.

LEVEL OF EVIDENCE

4.

Frequency and distribution pattern of minor salivary gland tumors in a northeastern Chinese population: a retrospective study of 485 patients

PURPOSE

The relative frequency of individual minor salivary gland tumors (MSGTs) is not well documented in the literature. The aim of this study was to determine the range and demographics of all histologically diagnosed MSGTs in a northeastern Chinese population.

MATERIALS AND METHODS

A total of 485 cases of MSGT were retrospectively studied. The files of the Department of Oral and Maxillofacial Pathology, School of Stomatology, China Medical University served as a source of material for this study. All epithelial tumors from minor salivary glands accessioned from August 2004 to April 2014 were analyzed for demographic features, anatomic location of tumors, and pathologic classification. Tumors were classified according to the 2005 World Health Organization classification of salivary gland tumors. Statistical analysis was performed using analysis of variance.

RESULTS

MSGTs were identified in 485 (2.60%) of 18,670 accessed cases. There were 268 (55.26%) benign and 217 (44.74%) malignant tumors. Female outnumbered male patients (male-to-female ratio, 1:1.43). The mean ages of patients with benign and malignant MSGTs were 47.58 and 51.51 years, respectively. Pleomorphic adenoma and adenoid cystic carcinoma were the most frequent types of benign and malignant tumors, respectively. The palate was the most commonly affected site (64.74%), followed by the buccal mucosa (7.63%) and the tongue (5.98%).

CONCLUSIONS

From the results of this study and a review of the literature, it is suggested that MSGTs in the northeastern Chinese population may be characterized by a higher incidence of MSGTs than in the populations of other reviewed regions, a higher incidence of myoepithelioma, a rarer occurrence of polymorphous low-grade adenocarcinoma, and an absence of canalicular adenoma occurrence.

Polymorphous low grade adenocarcinoma has a consistent p63+/p40- immunophenotype that helps distinguish it from adenoid cystic carcinoma and cellular pleomorphic adenoma

Polymorphous low grade adenocarcinoma (PLGA) is a tumor of minor salivary glands that exhibits considerable morphologic overlap with adenoid cystic carcinoma and cellular pleomorphic adenoma, especially in small biopsy specimens. Unlike these other tumor types. PLGAs do not harbor a myoepithelial component, yet their frequent positivity for p63 diminishes the usefulness of this particular myoepithelial marker as a discriminating immunostain. p40 is an antibody that recognizes ΔNp63, a p63 isoform that is more specific for true myoepithelial differentiation. As such, p40 immunostaining could help distinguish PLGAs from adenoid cystic carcinomas and pleomorphic adenomas. In this study, p63 and p40 immunohistochemistry was performed on paraffin embedded, formalin fixed tissue from 11 PLGAs, 101 adenoid cystic carcinomas, and 31 pleomorphic adenomas. All 11 PLGAs (100 %) were positive for p63 but completely negative for p40. Among adenoid cystic carcinomas, 91 of 101 (90 %) were positive for p63 and 90/101 (89 %) were positive for p40. The single discordant p63+/p40- adenoid cystic carcinoma exhibited solid architecture and high grade features not typically seen in PLGA. Among pleomorphic adenomas, 21/31 (68 %) were positive for p63 and 13/31 (42 %) were positive for p40. For the pleomorphic adenomas, the discordant p63+/p40- staining pattern was seen only in the overtly mesenchymal chondromyxoid stroma. The cellular epithelial component of the pleomorphic adenomas demonstrated concordant p63+/p40+ or p63-/p40- immunophenotypes. PLGA consistently exhibits a p63+/p40- immunophenotype that can help distinguish it from adenoid cystic carcinoma and cellular pleomorphic adenoma, tumors that characteristically demonstrate concordant p63 and p40 immunostaining patterns. A p63/p40 immunohistochemical panel can provide a valuable tool for making the distinction between these morphologically similar but clinically divergent entities.

Intraoral minor salivary gland tumours: a retrospective study from a dental and maxillofacial surgery centre in salem, Tamil Nadu

ABSTRACT

Minor salivary gland tumors (MSGTs) constitute a heterogeneous group of neoplasms with variation in histopathology. These are rare neoplasms usually occurring in the palate. Dental examination may provide an opportunity for early detection.

AIM

This study was undertaken to do an epidemiological survey of minor salivary gland tumours reporting to a single dental and maxillofacial surgery centre and to determine the correlation of the histopathologic characteristics with the clinical features.

MATERIALS AND METHODS

A retrospective survey of the histopathological findings of 1,020 consecutive biopsy reports in a single dental and maxillofacial surgery centre was done to identify cases of MSGT. The results were tabulated based on various criteria.

RESULTS

In our study, only 8 tumors were benign (26.67 %), and 22 tumors were malignant (73.33 %). Mucoepidermoid carcinoma (MEC) was the most common tumor (15 of 30). Pleomorphic adenoma was most common benign MSGT in our series (7 of 30). This was followed by adenoid cystic carcinoma (6 of 30). Palate was the most common site (13 of 30) followed by buccal mucosa (5 of 30) and lip (4 of 30).

CONCLUSIONS

Unlike many previous studies, malignant salivary gland tumours were predominant. MEC was the most common malignant tumour in our study similar to many other studies. The palate was the most common site for minor salivary gland neoplasms.

Polymorphous low-grade adenocarcinoma: an analysis of epidemiological studies and hints for pathologists

Background

This study is an analysis of the prevalence of polymorphous low grade adenocarcinoma (PLGA) in epidemiological surveys of salivary tumors published in the English language from 1992 to 2012.

Methods

These surveys included studies from different researchers, countries and continents. The 57 surveys for which it was possible to calculate the percentage of PLGAs among all malignant minor salivary gland tumors (MMSGT) were included in this review.

Results

The statistical analyses show significant differences in the PLGA percentage by time period, country and continent in the studies included in this review. The percentage of PLGAs among MMSGTs varied among the studies, ranging from 0.0% to 46.8%. PLGA rates have varied over the period studied and have most recently increased. The frequency of reported PLGA cases also varied from 0.0% to 24.8% by the country in which the MMSGT studies were performed. The PLGA percentages also varied significantly by continent, with frequencies ranging from 3.9% in Asia to 20.0% in Oceania

Conclusion

Based on these results, we concluded that although the accuracy of PLGA diagnoses has improved, they remain a challenge for pathologists. To facilitate PLGA diagnoses, we have therefore made some suggestions for pathologists regarding tumors composed of single-layer strands of cells that form all of the histological patterns present in the tumor, consistency of the cytological appearance and uniformly positive CK7, vimentin and S100 immunohistochemistry, which indicate a single PLGA phenotype.

Virtual slide

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1059098656858324

Minor salivary gland tumours of upper aerodigestive tract: a clinicopathological study

The aim of this retrospective study of 56 patients with minor salivary gland tumours (MSGTs) of the upper aerodigestive tract is to present demographic features, distribution of tumours as well as methods and results of treatment performed in our institution over a 10-year period. Of 221 patients with salivary gland tumours, 56 patients with MSGT were selected. There were 36 female and 20 male patients aged from 8 to 81 years. Male-to-female ratio was 1 : 2 in the group of benign MSGT and 1 : 1.7 in the group of malignant tumours. The palate was the most frequent site of MSGT (45.6%), followed by buccal mucosa (19.3%). Of all MSGTs 63.2% were malignant, and 36.8% were benign. Adenoid cystic carcinoma was the most common neoplasm (31.6%), followed by pleomorphic adenoma (29.8%). Surgery was the method of choice in the treatment of patients with MSGT. Postoperative defects were reconstructed by prosthetic obturators, local flaps, and free radial forearm flap. Relative survival for patients with malignant MSGT was 88% at three years and 71.5% at five years. MSGTs are more frequent in females and predominantly affect the palate. Malignant MSGTs are more common than benign.