neoplasms of the salivary glands: a descriptive
TRANSCRIPT
Kamulegeya1 The Journal of Contemporary Dental Practice, Volume 5,
No. 3, August 15, 2004
Neoplasms of the Salivary Glands: A Descriptive Retrospective Study of 142
Cases-Mulago Hospital Uganda
Objective: This study was aimed at establishing the prevalence, sex, age, and site distribution of salivary gland neoplasms as seen in the Department of Oral Surgery Mulago Hospital Uganda.
Design: Descriptive retrospective study.
Materials and Methods: Histopathological results from the Department of Oral Surgery were retrieved and analyzed for histological diagnosis, age, sex, and site. Records retrieved included those from January 1988 to December 2000. Student’s t-test and z-test were used for data analysis.
Results: Of all neoplasms seen in the Department between 1988 and 2000, salivary gland tumors com- prised 7.8% of which 77 (54.23%) were benign and 65 (45.77%) were malignant. Pleomorphic adenoma was the most prevalent over all. Among the malignant group, adenocarcinoma was the most prevalent of those where the palate was the most affected site. The age range was 1-80 years with the overall mean age being 33.83 ± 18. 83. The mean age for the benign lesions was 26.74 ± 16.0 and for the malignant lesions was 42.49 ± 19.15.
Conclusion: The findings were in agreement with most African studies but differed from studies from the other continents. Pleomorphic adenoma was the most prevalent salivary gland neoplasm with both males and females affected equally. More research is needed on specific salivary gland neoplasms in Uganda and preferentially on a regional basis geographically. However, if valid data on the diagnosis as well as age, site, and sex distribution are to be obtained, an improvement in the standardization of diagnosis and reporting of patient data will be necessary.
Keywords: Salivary gland neoplasms, pleomorphic adenoma, adenocarcinoma, Uganda
Citation: Kasangaki A, Kamulegeya A. Neoplasms of the Salivary Glands: A Descriptive Retrospective Study of 142 Cases-Mulago Hospital Uganda. J Contemp Dent Pract 2004 August;(5)3:016-027.
Abstract
© Seer Publishing
2 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Introduction Different diseases affect- ing the salivary glands affect the efficiency and normal function of the glands. The diseases range from infections, inflammation, obstruction, functional disorders, and neoplasms. Although in the general popula- tion, the prevalence of salivary gland neoplasms is relatively low in relation to other salivary gland diseases, they do constitute a significant proportion of oral tumors after squamous cell carcinoma.1 A study from Nigeria reports salivary gland neoplasms as 2.8% of all head and neck tumors.2 In Kenya they are among the most common oral tumors.3 While in Uganda, they ranked next to sarcomas, adamantinomas (ameloblastoma), and carcinomas.4 Despite the fact that globally benign salivary gland tumors predominate over malignant ones5-10, there is a variation in the prevalence of the specific salivary gland neoplasms from study to study worldwide. In the state of Oklahoma in the USA5, Jamaica6, and Japan11, muco-epidermoid carcinoma is the most prevalent malignant neoplasm, while in Britain12 adenoid cystic carcinoma predominates. In South Africa10 polymorphous low-grade adeno- carcinoma predominates. The most afflicted sites by these tumors also vary from study to study. For example, pleomorphic adenoma is the most common tumor in the parotid gland. Seventy five percent of these tumors are present in the parotid gland as compared to 39.8% in the palate.13 The situation in Uganda is not yet clearly known since we could only find one article4 on this subject. Sing et al. reports of a palatal location but the findings are about tumors of the jaws which may have included pleomorphic adenoma of the minor salivary glands of the palate.
The sex distribution of these neoplasms is also reported differently by different authors. A report from Brazil7 reports a slight female preponder- ance of minor salivary gland neoplasms, while the Jordanian study reports a slight male preponder- ance.8 Cawson1 reports salivary gland carcinoma preponderance for females, and Aritoba14 reports several sex preponderancies of different salivary gland neoplasms in relation to their location. The age distribution of patients with salivary neo- plasms differ.10,14,15,16
The purpose of this study was to establish the dif- ferent biopsed and histopathologically confirmed salivary gland neoplasms seen at the Department of Oral Surgery Mulago Hospital, their age, sex distribution, and site for a period between January 1988 to December 2000.
Materials and Methods A total of 142 salivary gland neoplasm reports were retrieved from the histopathological results files of the Department of Oral Surgery Mulago Hospital Kampala Uganda stretching from the year 1988-2000.
Clinical information including, age, sex, and site from which the biopsy was taken were recorded. The data was compiled manually onto a master sheet from which tallying was done. Both the t-test and z-test were used for data analysis.
We also went on to ask the pathologists for the criteria they use in the diagnosis of salivary gland tumors. A summary is provided in Table 1.
Results The distribution of the various salivary gland neoplasms is presented in Table 2. They com- prised 7.5% of all oral neoplasms. From the Department’s biopsy results file, (77) 54.23% of the lesions were benign and (65) 45.77% were malignant.
Of all the benign lesions, the most frequent was pleomorphic adenoma constituting 77.9%, fol- lowed by salivary gland adenoma 18.18%, and then oxyphil cell adenoma at 3.9%. Among the malignant salivary gland neoplasms, adenocarci- noma was the most prevalent at 36.92%, followed by carcinoma at 27.69%, then muco-epidermoid carcinoma 9.23%, mucus secreting carcinoma constituted 6.15%, acinic cell carcinoma 4.62%, and carcinoma ex pleomorphic adenoma 3.08%. Of the 142 cases, 64 (45.07%) were male, 76 (53.52% were female, and in 2 cases (1.41%) sex was not specified. The male:female ratio was 1: 1.18. Forty-three (55.84%) of the benign neo- plasms cases were female; while 33 (50.77%) of malignant cases were female and 2 (3.08%) of the malignant cases were unspecified. The gen- der distribution of these salivary gland neoplasms is shown in Table 2, and the age distribution of these cases is shown in Table 3. The mean age
3 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Table 1. Summary of diagnostic criteria.
4 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Table 1 (cont.). Summary of diagnostic criteria.
Table 2. The different salivary gland neoplasms; distribution by sex, diagnosis and working abbreviation.
5 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
for this patient population was 33.83 ± 18.83 with an age range of 1-80 years. The mean age of the benign neoplasms was 26.74 ± 16.0, while that of the malignant neoplasms was 42.49 ± 9.15. Most cases were in the second, third, fourth, and fifth decade of life with a peak incidence in the third decade (see Table 3 and Figure 1).
The mean age of the most prevalent neoplasms, i.e., pleomorphic adenoma had a mean age of 29 ± 15.74 with a range of 5-69 years and a peak in the third decade of life (Figure 1). The mean age of patients with salivary gland adenoma was 19.59 ± 1.73. Among the malignant salivary gland neoplasms, adenocarcinoma had a mean age of 47.17 ± 19.09, while adenoid cystic car- cinoma had a mean of 40.56 ± 17.09; salivary duct carcinoma and mucoe-pidermoid carcinoma had a mean age of 46.8 ± 18.28 and 38 ± 18.74, respectively.
The distribution of each type of salivary gland neoplasms as per site of biopsy is shown in Table 4. Of all the histopathological report slips, 47.1% did not have the site of biopsy specified. Among those whose site of biopsy was available, the pal- ate and parotid area were the most common sites 49.33% and 26.67%, respectively. (See Table 3 and Figure 2).
Discusion There are only a few reports available that have reviewed large studies of salivary gland neo- plasms worldwide. Eneroth reviewed 2328 cases between the years 1919-1969 and Chaudary et al. reviewed 1320 cases.17,18 More recently, addi- tional case studies have been reported: Williams et al., Maita et al., Abiose et al., Vargas et al., Chidzonga et al., and Onyango et al.2,6,8,16,19,21
Although there have been some reports on sali- vary gland neoplasms as a component of tumors of the oral facial area from Uganda4, no specific report is available from this part of the world on salivary gland neoplasms independent from other classification of tumors.
From Table 2 benign salivary gland neoplasms were more prevalent (54.3%), which is consis- tent with several other studies as can be seen in Table 5. Similar to Neely et al. our study shows an almost equal prevalence of benign and malig- nant tumors.5 In contrast, Williams et al. and
Vargas et al. reported significantly different preva- lences, although benign lesions still predominate.6,16
Among the benign group and on the over all, pleo- morphic adenoma was the most common salivary gland tumor. This agrees with previous studies (Table 5) and with more recent studies6,8,14,16,21, hence it seems the world over, Uganda inclusive, pleomorphic adenoma is the most common salivary gland tumor. Slide 6 shows one of the cases diag- nosed as pleomorphic adenoma.
Among the benign group, salivary gland adeno- ma was the second most common diagnosis. Unfortunately while Cawson reports it1, this diagno- sis does not exist in the World Health Organization (WHO) classification20 but could be the equivalent of monomorphic adenomas inclusive of adeno- lymphomas, a diagnosis not seen in these studies or other types since at least three cases of oxy- philic adenoma are reported. It must be noted in the WHO classification20 salivary gland adenoma comprises a group of fourteen tumors. The only subtype found in this study were pleomorphic ade- noma (42.3%) and oxyphylic cell adenoma (oncon- cytoma) 2.1%; the remaining adenomas (9.9%) were not further classified. The pathologists helped us review some adenomas and we discovered that adenomas as diagnosed varied from cannalicular, warthin’s tumor, to cystadenoma as can be seen in slides 3, 4, and 5; slide 6 shows pleomorphic adenoma. Hence,there is a need to review and standardize the diagnoses of the different patients’ specimens seen in the Department of Pathology according to the current International Classification of Diseases (ICD)/World Health Organization (WHO) classification.
6 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
The results of our study are in agreement with the study done in South Africa10; was found to be the most common salivary gland malig- nancy. However, other studies are in contrast with these findings2,5,6,7,11,12,16 with some rarely reporting this tumor.18,19 Furthermore in this study some adenocarcinomas were not sub typed; yet on review, variations were clear as can be seen in slides 1 and 2 showing unspecified and acinic cell adenocarcinoma, respectively. Thus, a combined effort to review African studies is needed to estab- lish whether this is an African phenomenon or just a regional one or whether reporting is standardized to a specific classification. Adenoid cystic carcinoma in this study was
found to be the second most prevalent tumor fol- lowed by muco-epidermoid carcinoma at 27.69% and 12.31%, respectively. This is similar to a report from Nigeria, which ranks both as the most common salivary gland neoplasms.2 Unlike the Jamaican and Brazilian studies6,16, adenoid cystic carcinoma predominates over muco-epidermoid carcinoma in our study. In this study salivary gland carcinoma was the third most common lesion at 9.23%. This diagnosis is not reported in other studies as can be seen from Table 5 and is not a diagnosis cited in the WHO classifica- tion20 further stressing the need for standardiza- tion of reporting. Mucus secreting carcinoma was reported in our study. As seen in Table 5, some researchers, but not all, reported this category of
Figure 1.
Figure 2. par = parotid gland, pal = palate, smf = submandibular gland & fl oor of the mouth, uns = unspecifi ed.
7 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Slides 1 and 2 show two different adenocarcinomas whose sub type was not specifi ed. However, on review they were sub typed as unspecifi ed and acinic cell adenocarcinoma, respectively.
Slide 1. Slide 2.
Slide 4. Slide 3.
Slide 5. Slide 6.
Slides 3, 4, and 5 were all diagnosed as adenomas, while slide 6 was diagnosed as pleomorphic adenoma. On review, slides 3, 4, and 5 were sub-typed as cannalicular, Warthin’s tumor, and cyst adenoma.
8 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Table 3. Age distribution of salivary gland neoplasms.
Table 4. Shows the sites from which the biopsy was taken and the diagnosis.
9 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
tumor. Cawson1 argues this is likely to belong to the epidermoid tumor group and could be consid- ered either benign or malignant. Acinic cell carci- noma constituted 4.6% of all salivary gland malig- nancy and 2.1% overall which is in agreement with other studies1,17,18 as being a rare salivary gland neoplasm. Carcinoma ex pleomorphic constituted (2 cases) 1.4% overall and 3.08% of all malignant lesions. Unfortunately, the references available to us hardly mentioned this tumor. Cawson attributes its rarity to carcinomatous changes in pleomor- phic adenoma occurring late, thus, rarely given a chance to get to this stage1. However, Lewis et al.22 reports non specified adenocarcinoma as one of the sub-types of this tumor, and Varga et al.16
also notes all the cases they saw had adenocar-
cinoma as the malignant component; it is unclear whether adenocarcinomas seen in this study might have been alternatively classified as carcinoma ex pleomorphic adenoma.
Of all cases in this study 53.5% were female, 45.1 were specified as male, and 1.4% were unspeci- fied. Thus, an almost equal sex distribution (p=0.05) which is in agreement with several other studies.2,4,5 The male to female ratio was 1:1.19, thus, no statistically significant difference in sex distribution. These statistics differ from those of Jordan8; hence, the question of possible geographical differences in their prevalence. Both malignant and benign neoplasms had equal sex distribution (p=0.05).
Table 5. Salivary gland neoplasms prevalence from present study along side other research findings.
10 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Pleomorphic adenoma had a slight preponder- ance for females with the male to female sex ratio being 1:1.3, which is in agreement with other find- ings.13 Unlike a report from Nigeria14, for all age groups, female distribution predominated over males. Salivary gland adenoma had equal sex distribution, but because no other study we came across recognized this entity we had nothing to compare with. All of the three cases of oxyphil cell adenoma were female though Cawson1 writes of a female preponderance; in this study we could not establish any sex preponderance due to the few cases found. Adenocarcinoma had equal sex distribution (p=0.05). However, for poorly dif- ferentiated adenocarcinoma, there was male pre- ponderance over female (p=0.05). Adenoid cystic carcinoma had female preponderance over male (p=0.05). The numbers of salivary gland carcino- ma, muco-epidermoid carcinoma, and acinic cell carcinoma were too few to comfortably establish sex preponderance. Carcinoma ex pleomorphic adenoma had only two cases, both being male.
The distribution of the salivary gland neo- plasms as per site of biopsy is shown in Table 4. Unfortunately, many of the biopsy sites in this study’s cases 47.18% were not recorded. Of those recorded, the palate featured greatly con- stituting 45.94%, followed by the parotid area 26.67%, and sub-mandibular area 16% (Table 4 and Figure 2). These results agree with a few other studies from Africa. The palatal neo- plasms had a preponderance for females 64.7% (p=0.005), a fact that was reported by Onyango et al.21 The parotid region was equally affected by both malignant and benign tumors, which is in contrast with other reports17,18, therefore, geo- graphical differences may exist.
Though pleomorphic adenoma is known to mainly affect the parotid gland1,17, in this study it affected the palate (p=0.05). The lip was affected in just three cases. Of the three lip lesions, two were malignant, i.e., adenoid cystic carcinoma and muco-epidermoid carcinoma with the third being salivary gland adenoma. Owens et al.24 reports adenoid cystic carcinoma and muco-epidermoid carcinoma as the most frequent malignant salivary gland neoplasms of the lip.
As reported by other authors elsewhere, our results agree with the findings that pleomorphic adenoma is common among adults and in the fact salivary neoplasms appear in the third, fourth, and fifth decade of life with a peak in the third decade (Table 3 and Figure 1). Though not reflected in either the tables or figures, the general overall presentation between the sexes, in terms of age at the time of reporting, revealed there were many more females with pleomorphic adenoma than males in the peak group.
Conclusion There are significant reporting differences by diag- nosis and a lack of information regarding the sites of lesions.
There is a geographic variation in the prevalence of salivary gland neoplasms according to sex, age, and site. More research into specific salivary gland neoplasms inclusive of treatment modalities, prognosis, and causative factors are needed in Uganda.
While the objective of this study was to establish the prevalence and site distribution of salivary gland neoplasms as seen in the Department of Oral Surgery Mulago Hospital, we realize a need for standardization and improved reporting by both the surgeons and pathologists.
11 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
References 1. Cawson RA. Essentials of dental surgery and pathology 4th edition. Churchill Livingstone Medical
Division of Longman Group UK Ltd. 1984. 298-311. ISBN 044304015X. 2. Abiose BO, Oyejide O, Ogunniyi J. Salivary gland tumours in Ibadan, Nigeria: a study of 295 cases.
Afr J Med Med Sci. 1990 Sep;19(3):195-9. 3. Onyango JF, Awange DO, Wakiaga JM. Oral tumours and tumour-like conditions in Kenya: I.
Histological distribution. East Afr Med J. 1995 Sep;72(9):560-3. 4. Pritam Singh and J.Cook. Tumors of the jaws.East African Medical Journal Oct. 1995 33(10): 383-
390 5. Neely MM, Rohrer MD, Young SK. Tumors of minor salivary glands and the analysis of 106 cases. J
Okla Dent Assoc. 1996 Spring;86(4):50-2. Review. 6. Williams NP, Boyd DL, Choy L, et. al. Salivary gland lesions: a Jamaican perspective. West Indian
Med J. 2001 Mar;50(1):62-5. 7. Loyola AM, de Araujo VC, de Sousa SO, et. al. Minor salivary gland tumours. A retrospective study
of 164 cases in a Brazilian population. Eur J Cancer B Oral Oncol. 1995 May;31B(3):197-201. 8. Jasser K Ma’aita, Nabih Al-Kaisi, Shawkat Al- Tamimi, Abdulwahab Wraikat. Salivary gland tumors in
Jordan: A retrospective study of 221 patients. The Croatian Medical Journal March 1999 Volume 40 Number 4 (Medline).
9. Idris AM, Ahmed HM, Mukhtar BI, et. al. Descriptive epidemiology of oral neoplasms in Sudan 1970- 1985 and the role of toombak. Int J Cancer. 1995 Apr 10;61(2):155-8.
10. van Heerden WF, Raubenheimer EJ. Intraoral salivary gland neoplasms: a retrospective study of seventy cases in an African population. Oral Surg Oral Med Oral Pathol. 1991 May;71(5):579-82.
11. Kusama K, Iwanari S, Aisaki K, et. al. Intraoral minor salivary gland tumors: a retrospective study of 129 cases. J Nihon Univ Sch Dent. 1997 Sep;39(3):128-32.
12. Eveson JW, Cawson RA. Tumours of the minor (oropharyngeal) salivary glands: a demographic study of 336 cases. J Oral Pathol. 1985 Jul;14(6):500-9.
13. Chidzonga MM, Lopez Perez VM, Portilla Alvarez AL Pleomorphic adenoma of the salivary glands. Clinicopathologic study of 206 cases in Zimbabwe. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1995 Jun;79(6):747-9.
14. Arotiba GT. Salivary gland neoplasms in Lagos, Nigeria. West Afr J Med. 1996 Jan-Mar;15(1):11-7. 15. J.V. Soames and J.C.Southam. Oral Pathology 2nd edition Oxford Medical Publications 1993, 245-
253. ISBN 0192622153 16. Vargas PA, Gerhard R, Araujo Filho VJ, et. al. Salivary gland tumors in a Brazilian population: a ret-
rospective study of 124 cases. Rev Hosp Clin Fac Med Sao Paulo. 2002 Nov-Dec;57(6):271-6. Epub 2003 Feb 17.
17. Eneroth CM. Salivary gland tumors in the parotid gland, submandibular gland, and the palate region. Cancer. 1971 Jun;27(6):1415-8. No abstract available.
18. Chaundry AP, Vickers RA, Gorlin RJ. Intraoral minor salivary gland tumors. An analysis of 1,414 cases. Oral Surg Oral Med Oral Pathol. 1961 Oct;14:1194-226. No abstract available.
19. Chidzonga MM, Lopez Perez VM, Portilla-Alvarez AL. Salivary gland tumours in Zimbabwe: report of 282 cases. Int J Oral Maxillofac Surg. 1995 Aug;24(4):293-7.
20. Seifert G, Brocheriou C, Cardesa A, et. al. WHO International Histological Classification of Tumours. Tentative Histological Classification of Salivary Gland Tumours. Pathol Res Pract. 1990 Oct;186(5): 555-81.
21. Onyango JF, Awange DO, Muthamia JM, et. al. Salivary gland tumours in Kenya. East Afr Med J. 1992 Sep;69(9):525-30. 69(9) 525-530.
22. Lewis JE, Olsen KD, Sebo TJ. Carcinoma ex pleomorphic adenoma: pathologic analysis of 73 cases. Hum Pathol. 2001 Jun;32(6):596-604.
23. Ezeanolue BC. Salivary gland neoplasms: a descriptive analysis of the pattern seen in Enugu. West Afr J Med. 1999 Jul-Sep;18(3):179-82.
24. Owens OT, Calcaterra TC. Salivary gland tumors of the lip. Arch Otolaryngol. 1982 Jan;108(1):45-7.
12 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
About the Authors
Neoplasms of the Salivary Glands: A Descriptive Retrospective Study of 142
Cases-Mulago Hospital Uganda
Objective: This study was aimed at establishing the prevalence, sex, age, and site distribution of salivary gland neoplasms as seen in the Department of Oral Surgery Mulago Hospital Uganda.
Design: Descriptive retrospective study.
Materials and Methods: Histopathological results from the Department of Oral Surgery were retrieved and analyzed for histological diagnosis, age, sex, and site. Records retrieved included those from January 1988 to December 2000. Student’s t-test and z-test were used for data analysis.
Results: Of all neoplasms seen in the Department between 1988 and 2000, salivary gland tumors com- prised 7.8% of which 77 (54.23%) were benign and 65 (45.77%) were malignant. Pleomorphic adenoma was the most prevalent over all. Among the malignant group, adenocarcinoma was the most prevalent of those where the palate was the most affected site. The age range was 1-80 years with the overall mean age being 33.83 ± 18. 83. The mean age for the benign lesions was 26.74 ± 16.0 and for the malignant lesions was 42.49 ± 19.15.
Conclusion: The findings were in agreement with most African studies but differed from studies from the other continents. Pleomorphic adenoma was the most prevalent salivary gland neoplasm with both males and females affected equally. More research is needed on specific salivary gland neoplasms in Uganda and preferentially on a regional basis geographically. However, if valid data on the diagnosis as well as age, site, and sex distribution are to be obtained, an improvement in the standardization of diagnosis and reporting of patient data will be necessary.
Keywords: Salivary gland neoplasms, pleomorphic adenoma, adenocarcinoma, Uganda
Citation: Kasangaki A, Kamulegeya A. Neoplasms of the Salivary Glands: A Descriptive Retrospective Study of 142 Cases-Mulago Hospital Uganda. J Contemp Dent Pract 2004 August;(5)3:016-027.
Abstract
© Seer Publishing
2 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Introduction Different diseases affect- ing the salivary glands affect the efficiency and normal function of the glands. The diseases range from infections, inflammation, obstruction, functional disorders, and neoplasms. Although in the general popula- tion, the prevalence of salivary gland neoplasms is relatively low in relation to other salivary gland diseases, they do constitute a significant proportion of oral tumors after squamous cell carcinoma.1 A study from Nigeria reports salivary gland neoplasms as 2.8% of all head and neck tumors.2 In Kenya they are among the most common oral tumors.3 While in Uganda, they ranked next to sarcomas, adamantinomas (ameloblastoma), and carcinomas.4 Despite the fact that globally benign salivary gland tumors predominate over malignant ones5-10, there is a variation in the prevalence of the specific salivary gland neoplasms from study to study worldwide. In the state of Oklahoma in the USA5, Jamaica6, and Japan11, muco-epidermoid carcinoma is the most prevalent malignant neoplasm, while in Britain12 adenoid cystic carcinoma predominates. In South Africa10 polymorphous low-grade adeno- carcinoma predominates. The most afflicted sites by these tumors also vary from study to study. For example, pleomorphic adenoma is the most common tumor in the parotid gland. Seventy five percent of these tumors are present in the parotid gland as compared to 39.8% in the palate.13 The situation in Uganda is not yet clearly known since we could only find one article4 on this subject. Sing et al. reports of a palatal location but the findings are about tumors of the jaws which may have included pleomorphic adenoma of the minor salivary glands of the palate.
The sex distribution of these neoplasms is also reported differently by different authors. A report from Brazil7 reports a slight female preponder- ance of minor salivary gland neoplasms, while the Jordanian study reports a slight male preponder- ance.8 Cawson1 reports salivary gland carcinoma preponderance for females, and Aritoba14 reports several sex preponderancies of different salivary gland neoplasms in relation to their location. The age distribution of patients with salivary neo- plasms differ.10,14,15,16
The purpose of this study was to establish the dif- ferent biopsed and histopathologically confirmed salivary gland neoplasms seen at the Department of Oral Surgery Mulago Hospital, their age, sex distribution, and site for a period between January 1988 to December 2000.
Materials and Methods A total of 142 salivary gland neoplasm reports were retrieved from the histopathological results files of the Department of Oral Surgery Mulago Hospital Kampala Uganda stretching from the year 1988-2000.
Clinical information including, age, sex, and site from which the biopsy was taken were recorded. The data was compiled manually onto a master sheet from which tallying was done. Both the t-test and z-test were used for data analysis.
We also went on to ask the pathologists for the criteria they use in the diagnosis of salivary gland tumors. A summary is provided in Table 1.
Results The distribution of the various salivary gland neoplasms is presented in Table 2. They com- prised 7.5% of all oral neoplasms. From the Department’s biopsy results file, (77) 54.23% of the lesions were benign and (65) 45.77% were malignant.
Of all the benign lesions, the most frequent was pleomorphic adenoma constituting 77.9%, fol- lowed by salivary gland adenoma 18.18%, and then oxyphil cell adenoma at 3.9%. Among the malignant salivary gland neoplasms, adenocarci- noma was the most prevalent at 36.92%, followed by carcinoma at 27.69%, then muco-epidermoid carcinoma 9.23%, mucus secreting carcinoma constituted 6.15%, acinic cell carcinoma 4.62%, and carcinoma ex pleomorphic adenoma 3.08%. Of the 142 cases, 64 (45.07%) were male, 76 (53.52% were female, and in 2 cases (1.41%) sex was not specified. The male:female ratio was 1: 1.18. Forty-three (55.84%) of the benign neo- plasms cases were female; while 33 (50.77%) of malignant cases were female and 2 (3.08%) of the malignant cases were unspecified. The gen- der distribution of these salivary gland neoplasms is shown in Table 2, and the age distribution of these cases is shown in Table 3. The mean age
3 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Table 1. Summary of diagnostic criteria.
4 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
Table 1 (cont.). Summary of diagnostic criteria.
Table 2. The different salivary gland neoplasms; distribution by sex, diagnosis and working abbreviation.
5 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
for this patient population was 33.83 ± 18.83 with an age range of 1-80 years. The mean age of the benign neoplasms was 26.74 ± 16.0, while that of the malignant neoplasms was 42.49 ± 9.15. Most cases were in the second, third, fourth, and fifth decade of life with a peak incidence in the third decade (see Table 3 and Figure 1).
The mean age of the most prevalent neoplasms, i.e., pleomorphic adenoma had a mean age of 29 ± 15.74 with a range of 5-69 years and a peak in the third decade of life (Figure 1). The mean age of patients with salivary gland adenoma was 19.59 ± 1.73. Among the malignant salivary gland neoplasms, adenocarcinoma had a mean age of 47.17 ± 19.09, while adenoid cystic car- cinoma had a mean of 40.56 ± 17.09; salivary duct carcinoma and mucoe-pidermoid carcinoma had a mean age of 46.8 ± 18.28 and 38 ± 18.74, respectively.
The distribution of each type of salivary gland neoplasms as per site of biopsy is shown in Table 4. Of all the histopathological report slips, 47.1% did not have the site of biopsy specified. Among those whose site of biopsy was available, the pal- ate and parotid area were the most common sites 49.33% and 26.67%, respectively. (See Table 3 and Figure 2).
Discusion There are only a few reports available that have reviewed large studies of salivary gland neo- plasms worldwide. Eneroth reviewed 2328 cases between the years 1919-1969 and Chaudary et al. reviewed 1320 cases.17,18 More recently, addi- tional case studies have been reported: Williams et al., Maita et al., Abiose et al., Vargas et al., Chidzonga et al., and Onyango et al.2,6,8,16,19,21
Although there have been some reports on sali- vary gland neoplasms as a component of tumors of the oral facial area from Uganda4, no specific report is available from this part of the world on salivary gland neoplasms independent from other classification of tumors.
From Table 2 benign salivary gland neoplasms were more prevalent (54.3%), which is consis- tent with several other studies as can be seen in Table 5. Similar to Neely et al. our study shows an almost equal prevalence of benign and malig- nant tumors.5 In contrast, Williams et al. and
Vargas et al. reported significantly different preva- lences, although benign lesions still predominate.6,16
Among the benign group and on the over all, pleo- morphic adenoma was the most common salivary gland tumor. This agrees with previous studies (Table 5) and with more recent studies6,8,14,16,21, hence it seems the world over, Uganda inclusive, pleomorphic adenoma is the most common salivary gland tumor. Slide 6 shows one of the cases diag- nosed as pleomorphic adenoma.
Among the benign group, salivary gland adeno- ma was the second most common diagnosis. Unfortunately while Cawson reports it1, this diagno- sis does not exist in the World Health Organization (WHO) classification20 but could be the equivalent of monomorphic adenomas inclusive of adeno- lymphomas, a diagnosis not seen in these studies or other types since at least three cases of oxy- philic adenoma are reported. It must be noted in the WHO classification20 salivary gland adenoma comprises a group of fourteen tumors. The only subtype found in this study were pleomorphic ade- noma (42.3%) and oxyphylic cell adenoma (oncon- cytoma) 2.1%; the remaining adenomas (9.9%) were not further classified. The pathologists helped us review some adenomas and we discovered that adenomas as diagnosed varied from cannalicular, warthin’s tumor, to cystadenoma as can be seen in slides 3, 4, and 5; slide 6 shows pleomorphic adenoma. Hence,there is a need to review and standardize the diagnoses of the different patients’ specimens seen in the Department of Pathology according to the current International Classification of Diseases (ICD)/World Health Organization (WHO) classification.
6 The Journal of Contemporary Dental Practice, Volume 5, No. 3, August 15, 2004
The results of our study are in agreement with the study done in South Africa10; was found to be the most common salivary gland malig- nancy. However, other studies are in contrast with these findings2,5,6,7,11,12,16 with some rarely reporting this tumor.18,19 Furthermore in this study some adenocarcinomas were not sub typed; yet on review, variations were clear as can be seen in slides 1 and 2 showing unspecified and acinic cell adenocarcinoma, respectively. Thus, a combined effort to review African studies is needed to estab- lish whether this is an African phenomenon or just a regional one or whether reporting is standardized to a specific classification. Adenoid cystic carcinoma in this study was
found to be the second most prevalent tumor fol- lowed by muco-epidermoid carcinoma at 27.69% and 12.31%, respectively. This is similar to a report from Nigeria, which ranks both as the most common salivary gland neoplasms.2 Unlike the Jamaican and Brazilian studies6,16, adenoid cystic carcinoma predominates over muco-epidermoid carcinoma in our study. In this study salivary gland carcinoma was the third most common lesion at 9.23%. This diagnosis is not reported in other studies as can be seen from Table 5 and is not a diagnosis cited in the WHO classifica- tion20 further stressing the need for standardiza- tion of reporting. Mucus secreting carcinoma was reported in our study. As seen in Table 5, some researchers, but not all, reported this category of
Figure 1.
Figure 2. par = parotid gland, pal = palate, smf = submandibular gland & fl oor of the mouth, uns = unspecifi ed.
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Slides 1 and 2 show two different adenocarcinomas whose sub type was not specifi ed. However, on review they were sub typed as unspecifi ed and acinic cell adenocarcinoma, respectively.
Slide 1. Slide 2.
Slide 4. Slide 3.
Slide 5. Slide 6.
Slides 3, 4, and 5 were all diagnosed as adenomas, while slide 6 was diagnosed as pleomorphic adenoma. On review, slides 3, 4, and 5 were sub-typed as cannalicular, Warthin’s tumor, and cyst adenoma.
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Table 3. Age distribution of salivary gland neoplasms.
Table 4. Shows the sites from which the biopsy was taken and the diagnosis.
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tumor. Cawson1 argues this is likely to belong to the epidermoid tumor group and could be consid- ered either benign or malignant. Acinic cell carci- noma constituted 4.6% of all salivary gland malig- nancy and 2.1% overall which is in agreement with other studies1,17,18 as being a rare salivary gland neoplasm. Carcinoma ex pleomorphic constituted (2 cases) 1.4% overall and 3.08% of all malignant lesions. Unfortunately, the references available to us hardly mentioned this tumor. Cawson attributes its rarity to carcinomatous changes in pleomor- phic adenoma occurring late, thus, rarely given a chance to get to this stage1. However, Lewis et al.22 reports non specified adenocarcinoma as one of the sub-types of this tumor, and Varga et al.16
also notes all the cases they saw had adenocar-
cinoma as the malignant component; it is unclear whether adenocarcinomas seen in this study might have been alternatively classified as carcinoma ex pleomorphic adenoma.
Of all cases in this study 53.5% were female, 45.1 were specified as male, and 1.4% were unspeci- fied. Thus, an almost equal sex distribution (p=0.05) which is in agreement with several other studies.2,4,5 The male to female ratio was 1:1.19, thus, no statistically significant difference in sex distribution. These statistics differ from those of Jordan8; hence, the question of possible geographical differences in their prevalence. Both malignant and benign neoplasms had equal sex distribution (p=0.05).
Table 5. Salivary gland neoplasms prevalence from present study along side other research findings.
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Pleomorphic adenoma had a slight preponder- ance for females with the male to female sex ratio being 1:1.3, which is in agreement with other find- ings.13 Unlike a report from Nigeria14, for all age groups, female distribution predominated over males. Salivary gland adenoma had equal sex distribution, but because no other study we came across recognized this entity we had nothing to compare with. All of the three cases of oxyphil cell adenoma were female though Cawson1 writes of a female preponderance; in this study we could not establish any sex preponderance due to the few cases found. Adenocarcinoma had equal sex distribution (p=0.05). However, for poorly dif- ferentiated adenocarcinoma, there was male pre- ponderance over female (p=0.05). Adenoid cystic carcinoma had female preponderance over male (p=0.05). The numbers of salivary gland carcino- ma, muco-epidermoid carcinoma, and acinic cell carcinoma were too few to comfortably establish sex preponderance. Carcinoma ex pleomorphic adenoma had only two cases, both being male.
The distribution of the salivary gland neo- plasms as per site of biopsy is shown in Table 4. Unfortunately, many of the biopsy sites in this study’s cases 47.18% were not recorded. Of those recorded, the palate featured greatly con- stituting 45.94%, followed by the parotid area 26.67%, and sub-mandibular area 16% (Table 4 and Figure 2). These results agree with a few other studies from Africa. The palatal neo- plasms had a preponderance for females 64.7% (p=0.005), a fact that was reported by Onyango et al.21 The parotid region was equally affected by both malignant and benign tumors, which is in contrast with other reports17,18, therefore, geo- graphical differences may exist.
Though pleomorphic adenoma is known to mainly affect the parotid gland1,17, in this study it affected the palate (p=0.05). The lip was affected in just three cases. Of the three lip lesions, two were malignant, i.e., adenoid cystic carcinoma and muco-epidermoid carcinoma with the third being salivary gland adenoma. Owens et al.24 reports adenoid cystic carcinoma and muco-epidermoid carcinoma as the most frequent malignant salivary gland neoplasms of the lip.
As reported by other authors elsewhere, our results agree with the findings that pleomorphic adenoma is common among adults and in the fact salivary neoplasms appear in the third, fourth, and fifth decade of life with a peak in the third decade (Table 3 and Figure 1). Though not reflected in either the tables or figures, the general overall presentation between the sexes, in terms of age at the time of reporting, revealed there were many more females with pleomorphic adenoma than males in the peak group.
Conclusion There are significant reporting differences by diag- nosis and a lack of information regarding the sites of lesions.
There is a geographic variation in the prevalence of salivary gland neoplasms according to sex, age, and site. More research into specific salivary gland neoplasms inclusive of treatment modalities, prognosis, and causative factors are needed in Uganda.
While the objective of this study was to establish the prevalence and site distribution of salivary gland neoplasms as seen in the Department of Oral Surgery Mulago Hospital, we realize a need for standardization and improved reporting by both the surgeons and pathologists.
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