Incidence Of Salivary Gland Tumors Research Articles

Salivary gland tumor incidence in adult patients in a tertiary hospital in Mexico from 2008 to 2019.

To determine the incidence of salivary gland tumors in a population of a tertiary hospital in the State of Mexico, and to describe demographic variables. An observational, cross-sectional and retrospective study of salivary gland tumors reported in a tertiary hospital in the State of Mexico in the period 2008-2019 is presented. A prevalence of 0.049% was found. There was no difference between sex in the studied population. Benign salivary gland tumors were the most frequent (86.7%). The age range most affected was 51-60 years. The most frequently found tumor was the pleomorphic adenoma, followed by Warthin's tumor. There was 13.33% of sialolipomas, and one myoepithelioma. There were no cases of sublingual gland tumors or minor salivary glands. Tumors of the major salivary glands are infrequent tumors; population cases from a central Mexican state and their demographic characteristics are presented to contribute to the information found in local and international literature.

FINE NEEDLE ASPIRATION CYTOLOGY OF SALIVARY GLAND LESIONS: REPORTING BY THE MILAN SYSTEM

Background: In the salivary gland lesions most common presentation is of a swelling or palpable mass of varying duration. In infective lesions, pain is another presenting feature. The most accurate method of diagnosing salivary gland lesions is histopathology, yet the role of ne needle aspiration cytology (FNAC) for the diagnosis of salivary gland masses is well documented and is signicantly accurate. The present study comprise analysis of FNAC of all salivary gland lesions using Milan system of classication. The present retrospective Material and Methods: study involves 234 cases of salivary gland swellings, referred for FNAC to the Department of Pathology, Government Medical College, Jammu for a period of ve years w.e.f November, 2016 to 31 October, 2021. This study includes cytomorphological features of various salivary gland lesions on FNAC and their classication by the Milan system of reporting. It was obs Results: erved that peak incidence of salivary gland tumours was seen in the age group of 31-45 yrs. The majority of benign lesions were seen in the age group 16-30 yrs and the malignant lesions were seen in the age group 46-61yrs. There was female predominance over the male with F:M ratio is 1.46:1. The most frequently involved site was parotid gland (48.7%) followed by submandibular gland (40.6%). 109 cases were diagnosed as non-neoplastic, 98 as benign and 16 cases as malignant. Conclusion: FNAC is an important diagnostic tool to clinch the correct diagnosis of salivary gland tumours Fine needle aspiration cytology was able to distinguish between non-neoplastic and neoplastic lesions and benign and malignant tumours

Clinicopathological Study of Salivary Gland Tumours

Background: Salivary gland tumours are relatively uncommon and constitute 3% to 10% of all head & neck neoplasms. The majority of salivary gland tumours arise in the parotid gland.
 Objectives: To search the clinicopathological presentation of salivary gland tumours.
 Methods: This was a cross sectional study.
 Results: The highest incidence of benign tumors was in the 3rd and 4th decade, whereas for malignant tumor it was the 5thdecade of life. Among 47 male patients, 72.3% had benign and 27.7% cases had malignant tumours. Out of 40 female patients 45% cases had benign and 55% cases had malignant tumours. With overall male: female ratio was 1.2:1. Among parotid gland tumours 62.32% had benign and 37.68% cases had malignant tumours. Out of 12 submandibular gland tumours 41.67% cases had benign and 58.33% cases had malignant tumours. Among 35 malignant tumours, 12 Mucoepidermoid carcinoma, the majority occurred in the parotid gland 10(83.3%) followed by submandibular gland 1(8.3%) and minor salivary glands 1(8.3%). Out of 11 cases reported as Adenoid cystic carcinoma, the majority involved submandibular gland 6(54.5%) followed by parotid gland 4(36.4%).
 Conclusion: Benign salivary gland tumours are more common than malignant ones. There is male preponderance in the incidence of salivary gland tumours. Pleomorphic adenoma is the most frequently encountered tumour among all salivary gland tumours.
 Bangladesh J Otorhinolaryngol 2022; 28(1): 96-102

EPIDEMIOLOGY MAJOR SALIVARY GLAND TUMOUR IN EASTERN INDONESIA

Introduction: Salivary glands tumours are relatively rare to find. There is still no adequate data about the incidence of salivary gland tumours in Eastern Indonesia. The main objective of this research was to evaluate the patient profile, location of tumour, histopathology, and management of salivary glands tumours. Methods: Descriptive retrospective used from January 2014 to December 2018, patients in Eastern Indonesia. Results: There are 47 patients with salivary glands tumours. Females were 55,3% and male were 44,7%. By age groups found that 60 years for 27,7%. Based on the histopathology classification, pleomorphic adenoma for 34%, Whartin tumour for 2.1%, mucoepidermoid carcinoma for 29,8%, adenocarcinoma for 6,4%, Acinic cell carcinoma for 6,4%. Cystic adenoid for 6,4%, Epithelial carcinoma for 14,8%. Based on the location of the tumour’s appearance, parotid gland for 85,1%, sub-mandibular gland for 8,6%, sublingual glands for 6,3%. Based by the incidences, first year for 25,5%, second year for 12,8%, third year for 21,3%, fourth year for 12,8%, fifth year for 27,6%. Conclusion: Salivary gland tumours in our institution more common in women, developed in people aged 31-45 years, the parotid gland is the most common site and the most common malignant tumours are mucoepidermoid carcinoma.

Primary Salivary Gland Tumors- A two years study at Nobel Medical College

Introduction: Salivary gland tumors are a heterogeneous group of neoplasms that are relatively rare but represent a wide variety of both benign and malignant histopathologic subtypes. The aim of this study was to find out the histopathological distribution of primary salivary gland tumors and correlate fine needle aspiration cytology reports with histological findings.Materials and Methods: A total of 83 patients attending the otorhinolaryngology department with salivary gland tumors were enrolled in our study. The histopathological findings were reported and correlated with cytological findings.Results: The mean age of the patient with salivary tumors was 43.11 ± 13.02 years. Out of 83 cases, 3 (3.6%) patients were diagnosed as inflammatory lesions, 64 (77.1%) patients had benign salivary gland tumors and 16 (19.3%) of patients had malignant salivary glands tumors in histopathology. The sensitivity and specificity of FNAC in this series for detecting salivary gland malignancy were 68.8% and 98.5% respectively with an overall diagnostic accuracy of 92.8%. The most common salivary gland tumor was found to be pleomorphic adenoma (56.6%) and the most common malignant salivary gland tumor was found to be mucoepidermoid carcinoma (19.3%). The comparison of the incidence of salivary gland tumors in various age groups showed a statisticallysignificant difference (p=0.009). 
 Conclusions: Benign salivary tumors are more common than malignant tumors with the most common occurrence in parotid glands. Pleomorphic adenoma is the most common benign tumor whereas; mucoepidermoid carcinoma is the most common malignant tumor in patients visiting Nobel medical college.

A clinical study of the incidence of salivary gland tumors in a tertiary care teaching hospital

Background: The salivary gland system of the upper aero digestive tract plays a critical role in the functions of digestion, respiration, communication, and overall homeostasis. The Salivary gland swellings can be broadly classified into inflammatory, non-inflammatory and neoplastic swellings like calculi, benign tumours such has pleomorphic adenoma, oncocytoma, Warthin's tumour, malignant tumors which include-adenocarcinoma, adenoid cystic carcinoma, undifferentiated carcinoma.Methods: The present cross-sectional study was conducted at the Department of general surgery, Sri Siddhartha Medical College over a period of 2 years from August 2016 to July 2018. All major salivary gland neoplastic swellings confirmed by FNAC were included in this study.Results: In our study 23 patients had major salivary gland tumours out of that 19 patients had parotid and 4 had submandibular major salivary gland tumour. In our study out 23 cases of salivary tumours 19 cases were benign and 4 cases were malignant, out of 19 cases of parotid tumours, 15 (78.94%) cases were seen in superficial lobe and 4 (21.06%) were in deep lobe, out of 23 salivary gland tumours, 19 (82.6%) cases were pleomorphic adenoma 3(13.05%) cases were mucoepidermoid carcinoma and one case (4.35%) was acinic cell carcinoma.Conclusions: Parotid gland was the most common site of origin of both benign and malignant tumours, Pleomorphic adenoma was the most common benign salivary gland tumour and mucoepidermoid carcinoma was the most frequent malignant neoplasm.

A clinicopathological study of salivary gland tumors

Background: To evaluate tumors involving major and minor salivary glands, histopathology is an essential diagnostic method and is the gold standard. This study was carried out to know the incidence of salivary gland tumors, their clinical presentation and diverse morphological patterns. Materials and Methods: A prospective cross-sectional descriptive study was carried out over a period of two years in the department of pathology, Yenepoya Medical College hospital, Mangalore.Data regarding patient demographicswas also recorded. All the epithelial salivary gland tumors were classified according toWHO (2005) histological classification. Results: In the present study, a total of 65 cases of salivary gland tumours was found and an age range of 10-79 years was observed. The most common site affected was the parotid gland 47 (72.31%). Among the 48 (73.85%) benign tumors, pleomorphic adenoma 40 (61.54 %) was most commontumor and remaining 17(26.15%) cases were malignant, of which mucoepidermoid carcinoma 8 (12.31%) was frequently observed. Conclusion: This study highlights the usefulness of histopathologicalstudy of salivary gland tumors with various morphological patterns of benign and malignant salivary gland tumors, which are of utmost value in planning the further management of the patient.

Clinicopathological Behavior and Oncological Outcomes of Malignant Parotid Tumors in a Pakistani Population.

IntroductionThe incidence of salivary gland tumors is influenced by geographical and racial factors resulting in diverse histology. While salivary gland tumors account for a low proportion of head and neck cancers, most malignant tumors of the salivary gland are located in the parotid gland. The goals of this study are to describe the clinicopathological behavior of malignant parotid tumors and explore oncological outcomes related to survival in our Pakistani tertiary care cancer hospital.MethodsWe conducted a retrospective analysis of 209 patients diagnosed with malignant parotid tumors from 2004 to 2016. Data such as demographics, age, gender, histology, grade, clinical and pathological stage, surgical treatment types and adjuvant modalities used were analyzed using SPSS software version 20. We used Kaplan Meier curves to analyze survival data.ResultsThe median patient age at diagnosis was 40 years, and the ratio of men to women was 1.2:1. Mucoepidermoid carcinoma was the most common histological variant (with a 50% incidence rate) followed by adenoid cystic carcinoma (13%), and adenocarcinoma (10%). Histology has further categorized these malignant tumors into low (34%), intermediate (28%), and high (21% ) grades. The American Joint Committee on Cancer, seventh edition, clinical staging was Stage I (21%), II (28%), III (15%), and IV (34%). The 5-year survival was 68%, and the 10-year survival was 45%.ConclusionMucoepidermoid carcinoma is the most common malignant parotid histology in our patient population. Advanced age, increased T stage (size > 4 cm), high-grade histology, and cervical nodal involvement decrease overall survival. Open biopsies, piecemeal excisions, and delayed presentation for radiotherapy post-surgery may also have role in adverse outcomes in these malignancies.

Histopathological study of salivary gland tumors.

Context:The salivary glands are the site of origin of a wide variety of neoplasms and are also relatively uncommon. The histopathology of these tumors is said to be the most complex and diverse of any organ in the body. The incidence of salivary gland tumors (SGTs) is claimed to be influenced by geographical and racial factors. Histopathological diagnosis plays a major role in the diagnosis of these neoplasms, with very few contribution using special stains, immunohistochemistry and cytogenetic studies.Aims:Aimed at understanding the epidemiological pattern of these tumors and to compare our findings with reports done elsewhere.Settings and Design:This is a retrospective study done at Pathology Department a Postgraduate Teaching Hospital, Tertiary Care Centre in Bagalkot, Karnataka, India. All the cases of SGTs, which had been recorded in a 3-year period from 2009 to 2012, were enrolled in the study.Subjects and Methods:Clinical data were recorded and analyzed with respect to gender, age, site and histopathologic type.Results:Data of 59 cases of SGTs were recorded, of which 43 (69.16%) cases were classified as benign tumors and 16 (22.39%) cases as malignant tumors. Male to female ratio (M/F) and the mean age of patients were 1:1.8 and 43 years, respectively. Pleomorphic adenoma (60.71%) and adenoid cystic carcinoma (14.94%) were the most common benign and malignant neoplasms.Conclusions:Although the SGTs encountered were similar in most of their characteristics to those reported in India and other countries, some differences such as relative frequency, age and gender prevalence were discovered.

Incidence of salivary gland tumors: A morphological study at Pathology Department of King Edward Medical University/Mayo Hospital, Lahore

This study was conducted to see the incidence of the lesions of Salivary Gland. All the cases of salivary tissues submitted to the Pathology Department of King Edward Medical University were taken at the end of year (Jan 2005-Dec2005) and reanalyzed. There were 42 cases of salivary glands, out of which 19(45%) were males and 23(55%) were females. Age range was 12-72 years. Major number of cases (17) were from parotid, whereas 15 were from submandibular, 04 and 06 were from sublingual and minor salivary glands like palate respectively. There were 25(59.52%) pleomorphic adenoma, 01(2.3%), 01(2.3%), 04(9.5%), 07(16.6%) were monomorphic adenoma, lymphoepithelioma, mucoepidermoid carcinoma, adenoid cystic carcinoma respectively. Only 04(9.5%) cases showed chronic sialadenitis.

Abstract 242: Evaluation of apoptosis-related microRNAs in salivary gland tumors

Abstract MicroRNAs (miRNAs) are a class of short non-coding RNAs that regulates gene expression post-transcriptionally, being important modulators of several cellular functions such as proliferation, apoptosis, differentiation, and cell signaling. Salivary gland tumors comprise a heterogeneous group of lesions with different histologic features and diverse clinical behavior accounting for about 3% of all head and neck tumors. The low incidence of salivary gland tumors, coupled with the large amount of different lesions present in this group, makes the diagnosis a challenging activity. Therefore, the identification of molecular markers for diagnosis and prognosis is so important, especially for this group of neoplasms. Apoptosis plays an important role during during morphogenesis of glandular structures, including salivary gland development and recent studies demonstrated that several miRNAs are involved in the control of apoptosis. The aim of the present study was to determine the expression of apoptosis-related miRNAs in salivary gland tumors. With this goal, 60 samples have been selected: 25 pleomorphic adenomas (most common benign tumor), 25 mucoepidermoid carcinomas (most common malignant tumor) and 10 normal salivary gland samples. miRNA expression was examined by Real Time RT-PCR (qPCR) using TaqMan miRNA Assays (miR-15a, miR-16, miR-17-5p, miR-20a, miR-21, miR-29 and miR-34). The relative microRNA expression level was normalized based on the expression of RNU48. Experiments were performed in duplicate for each data point. Considering up- or down-regulation as a 2-fold difference in expression relative to the normal tissue, we observed up-regulation of miR-15a, miR-16, miR-17-5p, miR-21, miR-29 and miR-34a in 76.0%, 60.0%, 47.8%, 80.0%, 84.0% and 96.0% of the pleomorphic adenoma samples, respectively. Down-regulation of miR-20a was observed in 75.0% of the pleomorphic adenoma samples. Normal expression of miR-15a, miR-16, miR-17-5p and miR-29 was observed in the mucoepidermoid carcinoma samples. Down-regulation of miR-20a was observed in 56.5% of the mucoepidermoid samples. An increased expression if miR-21 was observed in 90.9% of these samples. miR-34a is up-regulated in 73.9% of the mucoepidermoid carcinoma samples, suggesting an important role in the pathogenesis of these salivary gland tumor. Our study provides evidence of alterations in the expression of apoptosis-regulating miRNAs in salivary gland tumors, suggesting a possible involvement of these microRNAs in salivary gland tumorigenesis. Citation Format: Bianca T. Flores, Silvia V. Lourenço, Maria A. Nagai, Luiz Paulo Kowalski, Fernando A. Soares, Cláudia Coutinho-Camillo. Evaluation of apoptosis-related microRNAs in salivary gland tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 242. doi:10.1158/1538-7445.AM2015-242

Salivary Gland Tumor: A Review of 599 Cases in a Brazilian Population

Salivary gland tumors consist of a group of heterogeneous lesions with complex clinicopathological characteristics and distinct biological behaviors. Worldwide series show a contrast in the relative incidence of salivary gland tumors, with some discrepancies in clinicopathological data. The main aim of this study was to describe demographic characteristics of 599 cases in a population from Central Brazil over a 10-year period and compare these with other epidemiological studies. Benign tumors represented 78.3% of the cases. Women were the most affected (61%) and the male:female ratio was 1:1.6. Parotid gland tumors were the most frequent (68.5% of cases) and patient age ranged from 1 to 88 years-old (median of 45 years old). The most frequent tumors were pleomorphic adenomas (68.4%) and benign tumors were significantly more frequent in the parotid (75.9%), while malignant tumors were more frequent in the minor salivary glands (40%) (P < 0.05). In conclusion, women and the parotid gland were the most affected and pleomorphic adenoma was the most frequent lesion, followed by adenoid cystic carcinoma and Warthin's tumor.

Clinical analysis of salivary gland tumor cases in West China in past 50 years

In our study, 3461 cases of salivary gland tumor treated between 1955 and 2002 at West China Stomatology Hospital of Sichuan University were retrospectively analyzed, and compared with the previous reports. Measures such as age, tumor location, tumor histological type, and the nature of the growth (benign or malignant) were recorded at the same time. The findings are as follows: the average ages of salivary gland tumor patients were 41.38 years for the benign cases and 45.20 for the malignant ones; the male:female ratio was 0. 99:1 in the benign cases and 1.34:1 in the malignant ones; primary tumors were mostly in the parotid gland, palate and submandibular gland in sequence. Pleomorphic adenoma was the most frequent benign tumor followed by Warthin's tumor and basal cell adenoma, whereas mucoepidermoid carcinoma, adenoid cystic carcinoma and adenocarcinoma not otherwise specified were the most frequent malignant tumors. The incidence of salivary gland tumors increased with age. The male:female ratio of malignant tumors was higher than that of benign ones. The parotid gland and palate were the most common locations of salivary gland tumors. Pleomorphic adenoma and mucoepidermoid carcinoma were the most frequent benign and malignant tumors, respectively.

Modeling breast cancer in vivo and ex vivo reveals an essential role of Pin1 in tumorigenesis.

Phosphorylation on certain Ser/Thr-Pro motifs is a major oncogenic mechanism. The conformation and function of phosphorylated Ser/Thr-Pro motifs are further regulated by the prolyl isomerase Pin1. Pin1 is prevalently overexpressed in human cancers and implicated in oncogenesis. However, the role of Pin1 in oncogenesis in vivo is not known. We have shown that Pin1 ablation is highly effective in preventing oncogenic Neu or Ras from inducing cyclin D1 and breast cancer in mice, although it neither affects transgene expression nor mammary gland development. Moreover, we have developed an ex vivo assay to uncover that a significant fraction of primary mammary epithelial cells from Neu or Ras mice display various malignant properties long before they develop tumors in vivo. Importantly, these early transformed properties are effectively suppressed by Pin1 deletion, which can be fully rescued by overexpression of cyclin D1. Thus, Pin1 is essential for tumorigenesis and is an attractive anticancer target. Our ex vivo assay can be used to study early events of breast cancer development in genetically predisposed mice.

Salivary gland tumors in Uganda: clinical pathological study.

The incidence of salivary gland tumors is claimed to be influenced by geographical and racial factors. The pathological classification and nomenclature of salivary gland tumors as defined by WHO classification (1991), is accepted world-wide but little is available in the literature regarding the spectrum of salivary gland tumors in Africa in the basis of this classification. Such efforts would allow comparison and justify any differences between the black African population and the rest of the world. To outline the clinicopathological features of salivary gland tumors in Uganda. Makerere University, Faculty of Medicine, Department of Pathology. All epithelial tumors from major and minor salivary glands accessioned from 1979 to 1988 were analyzed in respect to sex and age of patients, anatomical location of the tumor and histological type. The histological diagnosis of each individual tumor was based on the 1991 WHO classification of salivary gland tumors. During the span of 10 years, 268 cases of salivary gland tumors were diagnosed. Of these, 113 (42.2%) were males, 148 (55.2%) females and in the remaining seven (2.6%) cases, the sex was not specified. The age range of the 247 patients with recorded ages was from 0.5 to 80 years. The mean age at diagnosis was 38.1 (SD =17.03) with the median of 38.0 years. Thirty four percent of tumors originated from the parotid, 33.2% from the submandibular and 32.8% from minor salivary glands. No tumor was implicated from the sublingual gland. There were a total of 125 (46.6%) malignant tumors and 143 (53.4%) benign tumors. The mean age of patients with malignant lesions (43.1 years; SD=16.75; median=44.00 years) was 9.6 years older than those with benign tumors (mean=33.5 years; SD=16.0; median=30.00 years). Pleomorphic adenoma was the most common benign tumor (74.8%), followed by myoepithelioma (9.8%). No Whartin's tumor was encountered. The malignant tumors were dominated by adenoid cystic carcinoma (28.8%) followed by mucoepidermoid carcinoma (21.6%). The pattern of distribution of salivary gland tumors in black African population seems to differ from that of Western series in that; i) females are more affected than males, ii) there is a low proportion of tumors from the parotid gland and high proportion of tumors from the submandibular and minor salivary glands, iii) the parotid and minor salivary gland tumors have more probability of being malignant than those tumors from the submandibular gland iv) the newly categorized pathological entities are common and v) Whartin's tumor is extremely rare in black African population.

Salivary Gland Tumors after Childhood Radiation Treatment for Benign Conditions of the Head and Neck: Dose-Response Relationships

We have investigated the dose-response relationships for the incidence of salivary gland tumors in a cohort of 2945 individuals who were irradiated as children between 1939-1962. Most of the patients were treated to reduce the size of their tonsils and adenoids. The mean dose to the salivary glands (+/-SD) was 4.2 +/- 1.7 Gy. Eighty-nine patients developed 91 salivary gland neoplasms; 22 had single malignancies, 64 had single benign neoplasms, 2 developed two separate benign neoplasms, and 1 developed a single neoplasm but did not have surgery. The majority (81 of 89) of the patients developed neoplasms in the parotid glands. Mucoepidermoid carcinomas were the most common malignancy and mixed (pleomorphic) adenomas were the most common benign neoplasm. For all salivary gland tumors, the excess relative risk per gray (ERR/Gy) was 0.82; however, the 95% confidence interval was wide (0.04, upper bound indeterminate). The trend was determined principally by benign tumors, as there was no dose-response relationship for salivary gland cancer, although there were too few cases to draw definitive conclusions. Overall, our study provides support for an association between salivary gland tumors and radiation exposure. Although most salivary gland tumors are benign and are usually readily detected, they may cause morbidity, and people who have been irradiated in the area should be monitored for their occurrence.

Comment on "Incidence of Salivary Gland Tumors among Atomic Bomb Survivors, 1950-1987. Evaluation of Radiation-Related Risk" by Land et al. (Radiat. Res. 146, 28-36, 1996)

In a recent article on the incidence of salivary gland tumors among A-bomb survivors, Land et al. reported significant increases in risk with increasing A-bomb dose avd found that most of the dose response was produced by malignant mucoepidermoid tumors and benign Warthin's tumors (1). With respect to these two histologies, we reanalyzed case-control data from a Los Angeles County study of tumors of the parotid gland (about 80% of salivary gland tumors arise in the parotid glands) diagnosed between 1976 and 1984 (2), the largest study of salivary gland tumors to date, designed to assess the risk of medical and dental radiography. Radiation treatment to the head or neck at least 5 years prior to diagnosis was used as a simple dichotomous exposure with which to test the histologyspecific hypothesis. Risk was highest but was not limited to malignant mucoepidermoid tumors (Table I); none of the benign tumors were Warthin's tumor. Thus our data provide limited support for the conclusions of the A-bomb survivor study of salivary gland tumors and radiation risk. TABLE I

Lung Cancer Risks: Comparing Radiation with Tobacco

In a recent article on the incidence of salivary gland tumors among A-bomb survivors, Land et al. reported significant increases in risk with increasing A-bomb dose avd found that most of the dose response was produced by malignant mucoepidermoid tumors and benign Warthin's tumors (1). With respect to these two histologies, we reanalyzed case-control data from a Los Angeles County study of tumors of the parotid gland (about 80% of salivary gland tumors arise in the parotid glands) diagnosed between 1976 and 1984 (2), the largest study of salivary gland tumors to date, designed to assess the risk of medical and dental radiography. Radiation treatment to the head or neck at least 5 years prior to diagnosis was used as a simple dichotomous exposure with which to test the histologyspecific hypothesis. Risk was highest but was not limited to malignant mucoepidermoid tumors (Table I); none of the benign tumors were Warthin's tumor. Thus our data provide limited support for the conclusions of the A-bomb survivor study of salivary gland tumors and radiation risk. TABLE I

Search for correlation of radon levels and incidence of salivary gland tumors

Studies were undertaken to determine if there is a statistical correlation between radon levels and the incidence of salivary gland tumors because of high levels of radon in Pennsylvania. In Part I of the study, the incidence of minor salivary gland tumors accessioned by Temple University, Emory University, and University of Southern California from 1986 to 1988 were correlated with average radon levels in the three locations with the use of standard statistical analyses. In Part II, the occurrence of malignant salivary gland tumors was obtained for each of the 67 counties in Pennsylvania from 1986 to 1988 and correlated statistically with radon levels and population figures in each of those counties. A statistically significant correlation between radon levels and incidence of salivary gland tumors could not be demonstrated in either case.

Intra-oral salivary gland tumours in the West Midlands.

Intra-oral salivary gland tumours reported from the West Midlands over the years 1975-88 were examined as to a number of epidemiological variables; the question as to their increasing incidence was also addressed. The findings were largely in agreement with those of most previous authors in that most of the tumours occurred in the palate, but whereas most of these were benign, a large proportion of those in other sites were malignant. However, firm conclusions are difficult to draw since there is much disagreement over reporting criteria. An international workshop and comprehensive tumour registries are required in order to determine more accurate data and conclusions. Similar cooperation is necessary in order to substantiate or refute the suggestion that the incidence of salivary gland tumours is increasing.