Abstract
Objective: To carry out a retrospective analysis of
all benign and malignant tumors of major and minor salivary glands which were diagnosed
at King Hussein Medical
Center during the years
between 2000 and 2006.
Methods: A total of 127 patients diagnosed to have
salivary gland tumors were retrieved from our histopathology data records
between 2000 and 2006. Most patients were originally treated at King Hussein
Medical Center,
and some at one of the peripheral military hospitals. All cases were
analyzed according to their sex and age distribution as well as the frequency of various
histopathological types and their anatomical sites.
Results: Of the 127 cases 84.3% of tumors were benign and 15.7% were
malignant. The mean age of the benign neoplasms was 43.3 years, and most of
these tumors were seen between the fourth and sixth decade of life. The mean
age for the malignant neoplasms was 51.1 years, and most cases were in the
sixth decade of life. There was a male predominance in both benign and malignant
salivary gland neoplasms. Among the benign salivary gland tumors, the
most frequent histological type was pleomorphic adenoma (57.9%) followed by Warthin’s tumor (35.5%).
Adenoid cystic carcinoma and
mucoepidermoid carcinoma were the most frequently encountered malignant
tumors accounting for 90% of all malignant tumors. The most commonly involved salivary
gland for benign and malignant tumors was the parotid gland. Of the minor salivary gland tumors, the
most frequently affected site was the palate (65%), and the most frequent tumor
encountered was pleomorphic adenoma (55%).
Conclusion: Salivary
gland tumor is a subject of considerable interest because of its not uncommon
occurrence and varied histological pattern.
This study describes the pathological features of salivary gland tumors in Jordan. The findings are in agreement with results
of most previously published research studies.
Key words: Salivary
gland, Tumor, Parotid,
Pleomorphic adenoma
JRMS
December 2009; 16(3): 36-41
Introduction
Salivary gland tumors pose a morphologically and clinically diverse group of neoplasms which may present significant diagnostic and management challenges to the pathologist and surgeon. These tumors are rare, with an overall incidence in the Western world of approximately 2.5 to 3.0 cases per 100,000 per year.(1)
Malignant salivary gland neoplasms
account for less than 0.5% of all malignancies and approximately 3% to 5% of allhead and neck cancers.(1,2) Most patients with malignant salivary gland tumors are in the sixth or seventh decade of life.(3) Although exposure to ionizing radiation has been implicated as a cause of salivary gland cancer, the etiology of most salivary gland cancers is largely undetermined.(2,4)
Table I. Distribution of benign salivary gland tumors
with respect to histological type and
age
|
Histological Type
|
Age
|
Total
|
|
1-10
|
11-20
|
21-30
|
31-40
|
41-50
|
51-60
|
61-70
|
71-80
|
|
Pleomorphic adenoma
|
1
|
6
|
12
|
16
|
9
|
13
|
2
|
3
|
62
|
|
Warthin’s tumor
|
-
|
-
|
1
|
3
|
6
|
13
|
15
|
-
|
38
|
|
Monomorphic adenoma
|
-
|
-
|
-
|
-
|
-
|
4
|
-
|
1
|
5
|
|
Myoepithelioma
|
-
|
-
|
1
|
-
|
-
|
-
|
-
|
-
|
1
|
|
Oncocytoma
|
-
|
-
|
-
|
1
|
-
|
-
|
-
|
-
|
1
|
|
Total
|
1
|
6
|
14
|
20
|
15
|
30
|
17
|
4
|
107
|
Table II. Distribution of malignant salivary gland tumors
with respect to histological type and age
|
Histological Type
|
Age
|
Total
|
|
1-10
|
11-20
|
21-30
|
31-40
|
41-50
|
51-60
|
61-70
|
71-80
|
|
Adenoid cystic carcinoma
|
-
|
-
|
-
|
2
|
1
|
6
|
-
|
-
|
9
|
|
Mucoepidermoid carcinoma
|
-
|
-
|
-
|
1
|
-
|
5
|
1
|
2
|
9
|
|
Adenocarcinoma
|
-
|
-
|
-
|
-
|
2
|
-
|
-
|
-
|
2
|
|
Total
|
-
|
-
|
-
|
3
|
3
|
11
|
1
|
2
|
20 |
Tumors of the salivary glands comprise those in the major salivary
glands such as the parotid, submandibular, and sublingual glands, and those in
the minor salivary glands such as the oral mucosa, palate, uvula, floor of
mouth, posterior tongue, retromolar area, peritonsillar area, pharynx, larynx,
and paranasal sinuses.(2,5)
Of all salivary
gland neoplasms over 50% are benign and approximately 70% to 80% of them
originate in the parotid gland.(1,2,6) The palate is the most
common site for minor salivary gland tumors. The frequency of malignant lesions
varies according to the site. Approximately
20% to 25% of parotid tumors, 35% to 40% of submandibular tumors, 50% of tumors
of the palate, and more than 90% of sublingual gland tumors are malignant.(1)
Histologically,
salivary gland tumors represent a most heterogenous group of tumors.(7)
There are 40 histological types of epithelial tumors which are known to
arise in the salivary glands. However some are exceedingly rare and may have
been the subject of only a few case reports.(1) The most common benign major and minor
salivary gland tumor is pleomorphic adenoma, which accounts for about 50% of
all salivary gland tumors and 65% of parotid gland tumors.(1)
The most common malignant major and minor salivary gland tumor is
mucoepidermoid carcinoma, which accounts for about 10% of all salivary gland
neoplasms and approximately 35% of all malignant salivary gland neoplasms.(1,8)
Mucoepidermoid carcinoma occurs most often in the parotid gland.(2,8,9)
The aim of the
present study is to retrospectively analyze benign and malignant tumors of
major and minor salivary glands encountered in Jordanian military hospitals.
Methods
We reviewed the pathology reports of 127
patients with salivary gland tumors treated at King Hussein Medical Center (KHMC)
as well as peripheral military hospitals of the Royal Medical Services between
2000 and 2006. Hospitals involved were distributed all over Jordan and provided medical
services for military personnel as well as civilians.
Diagnosis of individual tumours was based
on the World Health Organisation classification of salivary gland tumors (1991).
All tumors from major and minor salivary glands accessioned
between 2000 and 2006 at the
laboratory of Pathology and Cytology Division of Princess Iman Research Laboratory
Sciences at KHMC were reviewed by at least two pathologists.
Data analyzed included sex and age of patients, anatomical site and histopathological type.
Results
Age distribution of the various salivary
gland neoplasms is shown in Tables I and II.
Mean age for benign and malignant neoplasms
was 43.3 and 51.1 years, with peaks during the fourth and sixth decades and
sixth decade of life, respectively.
Mean age of the most prevalent neoplasm,
namely, pleomorphic adenoma was 40.4 years with an age range of 8 to 80 years and a peak incidence in the fourth decade of life. Mean age of patients with Warthin’s tumor was 56.2 years. Among malignant salivary gland neoplasms, adenoid cystic carcinoma showed a mean age of 49.2 years, while mucoepidermoid carcinoma showed a mean age of 61.9 years.
Table III. Distribution of benign salivary gland tumors in
respect to histological type and gender
|
Histological Type
|
Gender
|
Total
|
|
Female
|
Male
|
|
Pleomorphic adenoma
|
30
|
32
|
62 (57.9%)
|
|
Warthin’s tumor
|
6
|
32
|
38 (35.5%)
|
|
Monomorphic adenoma
|
3
|
2
|
5 (4.7%)
|
|
Myoepithelioma
|
1
|
-
|
1 (0.9%)
|
|
Oncocytoma
|
1
|
-
|
1 (0.9%)
|
|
Total
|
41
|
66
|
107 (100%)
|
Table IV. Distribution of malignant salivary gland tumors
with respect to histological type and gender
|
Histological Type
|
Gender
|
Total
|
|
Female
|
Male
|
|
Adenoid cystic carcinoma
|
2
|
7
|
9 (45%)
|
|
Mucoepidermoid carcinoma
|
3
|
6
|
9 (45%)
|
|
Adenocarcinoma
|
2
|
-
|
2 (10%)
|
|
Total
|
7
|
13
|
20 (100%)
|
Table V. Frequency of benign and malignant salivary
gland tumors with respect to histological type
|
Histological type
|
Total
|
Percentage
|
|
Pleomorphic adenoma
|
62
|
48.8
|
|
Warthin’s tumor
|
38
|
29.9
|
|
Monomorphic adenoma
|
5
|
3.9
|
|
Myoepithelioma
|
1
|
0.8
|
|
Oncocytoma
|
1
|
0.8
|
|
Adenoid cystic carcinoma
|
9
|
7
|
|
Mucoepidermoid carcinoma
|
9
|
7
|
|
Adenocarcinoma
|
2
|
1.6
|
|
Total
|
127
|
100 |
Sex distribution of salivary gland
neoplasms is shown in Table III and IV. Of the 127 cases, 79 (62.2%) were males,
48 (37.8%) were females. The male to female ratio was 1.6:1. There was a male predominance of benign and malignant
salivary gland neoplasms with male to female ratio of 1.6:1 and 1.9:1
respectively.
Frequency of benign and malignant salivary
gland tumors in respect to histological type is shown in Table V. Out of 127
cases, 84.3% (n=107) were benign and 15.7% (n=20) were malignant. Pleomorphic adenoma accounted for 57.9% of
benign salivary gland tumors and 48.8% (n=62) of
all cases, followed by Warthin’s
tumor (35.5% and 29.9 respectively). Other reported benign tumors were monomorphic
adenoma (4.7%), myoepithelioma (0.9%) and oncocytoma (0.9%).
Among
malignant salivary gland
tumors, adenoid cystic carcinoma and mucoepidermoid carcinoma were the
most frequent, accounting for 90% of all malignant tumors. Adenocarcinoma was
seen in two cases (10%).
Distribution of benign and malignant salivary gland tumors in respect to
anatomical site is shown in Tables VI and VII. The most affected site
for benign tumors was the parotid (75.7%), followed by minor glands (13%),
submandibular gland (10.2%) and sublingual gland (0.93%). The parotid gland was also the most frequent
site for malignant tumors (55%), followed by minor (30%) and submandibular
glands (15%).
Distribution
of minor salivary gland
tumors in respect to histological type and anatomical site is shown in Table VIII.
The most affected site was the palate (65%) and the most frequent
tumor was pleomorphic adenoma (55%).
Discussion
In this present study
of 127 major and minor salivary gland tumors, we saw predominance of benign
(84.3%) over malignant tumors (15.7%).
Table VI. Distribution of benign salivary gland tumors in
respect to histological type and
anatomical site
|
Histological type
|
Site
|
Total
|
|
Parotid
|
Submandibular
|
Sublingual
|
Minor
|
|
Pleomorphic adenoma
|
40
|
10
|
1
|
11
|
62
|
|
Warthin’s tumor
|
37
|
1
|
-
|
-
|
38
|
|
Monomorphic adenoma
|
3
|
-
|
-
|
2
|
5
|
|
Myoepithelioma
|
-
|
-
|
-
|
1
|
1
|
|
Oncocytoma
|
1
|
-
|
-
|
-
|
1
|
|
Total
|
81
|
11
|
1
|
14
|
107
|
Table VII. Distribution of malignant salivary gland tumors
in respect to histological type and
anatomical site
|
Histological type
|
Site
|
Total
|
|
Parotid
|
Submandibular
|
Sublingual
|
Minor
|
|
Adenoid cystic carcinoma
|
5
|
1
|
-
|
3
|
9
|
|
Mucoepidermoid carcinoma
|
6
|
2
|
-
|
1
|
9
|
|
Adenocarcinoma
|
-
|
-
|
-
|
2
|
2
|
|
Total
|
11
|
3
|
-
|
6
|
20
|
Table VIII. Distribution of minor salivary gland tumors in
respect to histological type and
anatomical site
|
Histological type
|
Site
|
Total
|
|
Palate
|
Lip
|
Floor of mouth
|
Nose
|
|
Pleomorphic adenoma
|
8
|
2
|
-
|
1
|
11
|
|
Monomorphic adenoma
|
1
|
-
|
1
|
-
|
2
|
|
Myoepithelioma
|
1
|
-
|
-
|
-
|
1
|
|
Adenoid cystic carcinoma
|
-
|
-
|
2
|
1
|
3
|
|
Mucoepidermoid carcinoma
|
1
|
-
|
-
|
-
|
1
|
|
Adenocarcinoma
|
2
|
-
|
-
|
-
|
2
|
|
Total
|
13
|
2
|
3
|
2
|
20
|
Similarly, Ma'aita et al.(10) analyzing 221 salivary
gland tumors in a Jordanian population, found 151 benign and 70 malignant
tumors. Satko et al.(11) analyzing a group of
1021 Slovakian patients with salivary gland tumors, observed higher frequency
of benign tumors (74%) versus malignant tumors (26%). Osuch-Wojcikiewicz et
al.(12) studying 332 Polish patients with salivary
gland tumors, reported 275 benign and 57 malignant tumors. In contrast, Poomsawat
et al.(13) who retrospectively
studied 60 cases of salivary gland tumors in a Thai population found a
predominance of malignant tumors with 68.3% being malignant and 31.7% being benign.
The vast majority of
our salivary gland tumors occurred in the parotid gland (72.4%). A similar
finding was reported by Luukkaa et al.(14) who evaluated 237 cases
of salivary gland tumors in Finland
and where the parotid gland was involved in 64% of the cases.
In our study, one case
of salivary gland tumor was noted in the sublingual gland. This demonstrates a
low prevalence of sublingual tumors, as has been reported by Eveson et al.(15) who also observed one
single sublingual tumor against 100 parotid tumors. Similarly, Ma'aita et al.(10) reported one
sublingual tumor (0.4%) among 221 cases. In contrast, Satko et al.(11) reported sublingual
tumors in 33 out of 1021 salivary gland tumors, which presented a higher
incidence (3.2%) than that of minor salivary gland tumors (3%).
We found higher
prevalence of salivary gland tumors in males (62.2%) than in females (37.8%). Peak
incidence was in the sixth decade. Similar findings were reported by Gonzalez et
al.(16) who observed a predominance of salivary gland
tumors in the male group (58.75%) and in the seventh decade of age. In
contrast, Ito et al.(17) who analyzed 496 cases
of salivary gland tumors in a Brazilian population found slight female
predominance with male to female ratio of 1:1.2.
Regarding histological
types diagnosed in this study, pleomorphic adenoma was the most frequent
(48.8%), as well as among benign neoplasms (57.9%), which is in accordance with
most published series around the world.(11,12,16) Out of 62 cases of
pleomorphic adenoma, 32 (51.6%) occurred in men, with a peak incidence in the sixth
decade of life. A similar observation was reported by Ma'aita et al.(10) Conversely, other
studies reported those lesions to be predominant in women.(18) Pleomorphic adenoma in
this study was most frequently seen in the parotid gland; and it was the most
frequent histological type in other salivary glands, which was in agreement
with other published reports.(19)
Warthin's tumor
comprised 35.5% of all benign tumors and 29.9% of all salivary gland tumors and
97.4% of cases found in the parotid gland. In European and American series this
tumor accounts between 5-20% of all salivary gland tumors.(15,20) Although it is known
to occur exclusively in the parotid gland, we have reported one case in the
submandibular gland. Similar finding was reported by another study on salivary
gland tumors in Jordan.(10)
Malignant neoplasms of
salivary glands totaled 20 cases out of all cases in this study (15.7%), among
which adenoid cystic carcinoma and muco-epidermoid carcinoma were the most frequent
neoplasms accounting for 90% of all malignant tumors. Adenocarcinoma was seen
in two cases (10%). These findings are supported by some publications,(21) but are in
disagreement with other studies reporting mucoepidermoid carcinoma as the most
frequent malignancy.(22)
Regarding minor salivary gland tumors the
most affected site was the palate (65%) and the most frequent tumor seen was pleomorphic
adenoma (55%) while adenoid cystic carcinoma was the most frequent malignant
tumor. Similar findings were reported by Li et al.(23)
Conclusion
Salivary gland tumor is a subject of considerable interest
because of its not uncommon occurrence and varied histological pattern.
This study for the first time reports the pathological features of salivary
gland tumors in Jordan. Our findings were in agreement with
results of most previously published research studies.
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