|Year : 2021 | Volume
| Issue : 2 | Page : 67-72
Salivary gland tumors – An unusual experience of 17 years
Subbiah Shanmugam, Sujay Susikar, M Samanth Kumar
Department of Surgical Oncology, Royapettah Govt Hospital, Chennai, Tamil Nadu, India
|Date of Submission||20-Sep-2020|
|Date of Acceptance||03-Jun-2021|
|Date of Web Publication||09-Dec-2021|
Dr. Subbiah Shanmugam
Department of Surgical Oncology, Royapettah Govt Hospital, Royapettah, Chennai - 600 014, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Objective: The salivary gland tumors or otherwise called the “unusual tumors” are aptly named. The aim of this study was to determine the types, frequency, distribution, and demographic characteristics and treatment–outcome aspects of salivary gland tumors in a large representative sample from southern peninsular India. Thereby, an attempt was made to understand to why are they actually called unusually presenting usual tumors. Materials and Methods: This original article is a retrospective study regarding a 17-year single institutional experience of these tumors with yet again unusual patterns of presentations. This work was harvested from an oncological unit in the southern part of India, the Royapettah Govt Hospital. Medical records from 2002 to 2019 of salivary gland tumor patients were compiled to derive the data and analyzed. Statistical Analysis Used: The data were grouped and analyzed using simple measures of central tendency, percentages, and represented in tables and graphs. Results: There are some similarities but more dissimilarities with respect to their presentation. Males outnumbered females. Malignant tumors outnumbered benign tumors. However, the most common benign and malignant tumors were similar to the rest of the world. Conclusion: A much confluent and in-depth analysis from other parts of India as well as other regions of the Asian subcontinent and world needs to be done to understand the behavior of these usual tumors presenting unusually.
Keywords: Acinic cell carcinoma, carcinoma ex pleomorphica, mucoepidermoid carcinoma, pleomorphic adenoma, Warthin's tumor
|How to cite this article:|
Shanmugam S, Susikar S, Kumar M S. Salivary gland tumors – An unusual experience of 17 years. Ann Indian Acad Otorhinolaryngol Head Neck Surg 2021;5:67-72
|How to cite this URL:|
Shanmugam S, Susikar S, Kumar M S. Salivary gland tumors – An unusual experience of 17 years. Ann Indian Acad Otorhinolaryngol Head Neck Surg [serial online] 2021 [cited 2022 Jan 21];5:67-72. Available from: https://www.aiaohns.in/text.asp?2021/5/2/67/332062
| Introduction|| |
Salivary gland tumors are rare, generating much interest not only due to complex anatomy and relative infrequency but also due to variable biological behavior. There are several studies involving large series of salivary gland tumors in various parts of world but only few are from India. With this background, we intend to perform a retrospective study representing 17 years of experience of salivary gland tumors from a single institution in the southern part of India. The aim of this study was to determine the types, frequency, distribution, and demographic characteristics of salivary gland tumors in a large representative sample. An attempt to evaluate the treatment and outcomes was also made to understand the behavior of these tumors.
| Materials and Methods|| |
The medical records of patients with salivary gland tumors treated in the Department of Surgical Oncology were reviewed retrospectively. The period of review covered 17 years, i.e., from January 1, 2002, to December 31, 2019. Patients with primary salivary gland tumors who underwent treatment in this institute during the mentioned time frame were included. The exclusion criteria included cancers other than those arising from salivary glands. All cases were classified according to the World Health Organization's histological typing of salivary gland tumors classification (2005). We have reviewed the histopathology of the tumors previously termed as “monomorphic adenoma” and “adenocarcinoma of nasal cavity” and reclassified them according to the same WHO Classification. The clinical features, including age, gender, histological type, location, treatment done, and recurrences after initial treatment of the tumors were obtained from clinical records. Data were presented as the mean and percentages, depicted in tables, pie charts, line diagrams, and bar diagrams.
| Results|| |
During the 17-year period, 111 patients with salivary gland tumors underwent treatment. Males constituted 56.76% (63 patients) and 48 females constituted 43.24% (48 patients). Out of 111, 25 (22.5%) were benign and the rest 86 (77.4%) were malignant lesions. The mean age at presentation was 47 years (range 14 years to 80 years). The average age of patients with benign tumors was 43 years and for patients with malignant tumors, the average age was 49 years [Figure 1] and [Figure 2]. The distribution of salivary gland tumors according to location and histology is presented in [Table 1] and [Figure 3]. Ninety-seven tumors (87.38%) occurred in the major salivary glands and the rest 14 tumors (12.61%%) were distributed in minor salivary glands. Among the major salivary glands, the most common site was the parotid gland (77 cases [69.36%]), followed by the submandibular salivary glands (19 cases [17.11%]) and one case of sublingual gland (0.009%). Among the minor salivary glands, hard palate was the most frequent site (6 patients), followed by the maxillary sinus (3 patients) and one case each was found in lip, tongue, tonsil, soft palate, and larynx [Table 2].
Pleomorphic adenoma was the most common benign tumor, found in 19 patients (76% of benign tumors), followed by Warthin's tumor, found in four patients (16% of benign tumors). Basal cell adenoma and lipoma were found in one patient each. Mucoepidermoid carcinoma was the most common malignant tumor found in 48 patients (43.24%), followed by adenoid cystic carcinoma (14 patients [12.6%]), carcinoma ex pleomorphica (9 patients [8.1%]), acinic cell carcinoma (8 patients [7.2%]), adenocarcinoma (4 patients [3.6%]), and one case each (0.9%) of myoepithelial carcinoma and squamous cell carcinoma [Table 1].
Benign tumors were reported only in major salivary glands and among them, pleomorphic adenoma was most commonly found in the parotid gland (12 patients), followed by submandibular gland (7 patients). The other benign tumors such as Warthin's tumor, basal cell adenoma, and lipoma were also found in parotid gland only [Figure 4].
Parotid gland reported 18 benign tumors and 59 malignant tumors. Among the malignant tumors of the parotid gland, 26 were mucoepidermoid carcinomas, 11 were adenoid cystic carcinomas, 9 were carcinoma ex pleomorphica, 8 were acinic cell carcinomas, 3 were adenocarcinoma, one was myoepithelial carcinoma, and squamous cell carcinoma with sebaceous differentiation was also found in one patient [Figure 5]. Submandibular gland reported 7 benign and 12 malignant tumors. Pleomorphic adenoma was the most common and the only benign tumor found in submandibular salivary gland. So also, mucoepidermoid carcinoma was the most common and the only malignant tumor found in submandibular salivary gland. In the sublingual gland, no benign tumor was found; however, only one malignant tumor was found which was mucoepidermoid carcinoma. Of all minor salivary gland tumors, none were benign and all were malignant [Table 1]. Mucoepidermoid carcinoma was the most common malignant tumor (9 patients), followed by adenoid cystic carcinoma (4 patients) and adenocarcinoma was found in one patient.
Of the 111 patients, 106 patients were operated, whereas four patients (0.036% of total) presented with advanced metastatic or unresectable disease wherein the patients were referred for palliative treatment and one patient of mucoepidermoid carcinoma of soft palate defaulted treatment. Most patients presented with swelling in the local regions. Pain was the second most common symptom, found in 37 patients (33.33% of total). Twenty-one patients (18.91% of total) presented with facial nerve palsy, of which 4 had benign tumor (pleomorphic adenoma) and 17 had malignant tumor. Nonhealing ulcer was the most common presentation for minor salivary gland tumors of hard palate, soft palate, lip, tonsil, and tongue. Patients of maxillary tumors presented with swelling and pain near cheekbone. Patients with benign tumors of parotid were operated on with either superficial parotidectomy or radical parotidectomy (if associated with facial nerve palsy). Total conservative parotidectomy was done for malignant lesions of parotid without facial palsy and radical parotidectomy was done for malignant lesions of parotid with facial nerve palsy. Extended radical parotidectomy with pectoralis major myocutaneous flap reconstruction was done for malignant lesions of parotid involving skin and also for recurrent parotid tumors with skin involvement. For benign lesions of submandibular gland, a simple excision was done, and for malignant lesions, a formal supra-omohyoid neck dissection was done. In adjuvant setup, 33 patients required radiotherapy, high-grade malignancy being the most common indication. Of the patients who were operated on, 16 patients (0.15% of operated patients) had local recurrence; among whom, seven patients recurred after superficial parotidectomy for pleomorphic adenoma. All these seven patients underwent reresection followed by radiotherapy. This summed up to a total of forty patients receiving radiotherapy. The treatment aspects and recurrence outcomes are illustrated in [Table 3]. The two patients who recurred after treatment for mucoepidermoid carcinoma of minor salivary gland in maxilla defaulted treatment after recurrence.
| Discussion|| |
Worldwide, they account for 3%–4% of head-and-neck cancers with an age-standardized incidence of 0.52–0.71/lakh population. Ackerman and Del Regato, 1970, described them as “The usual tumor of the salivary gland is a tumor in which the benign variant is less benign than the usual benign tumor and the malignant tumor is less malignant than the usual malignant tumor.” Epidemiological studies are often based on limited clinical numbers as the incidence of these tumors is less and their histological classification is comparatively difficult due to morphologic heterogeneity. The salivary glands are dispersed throughout the upper aerodigestive tract. Most tumors arising from parotid gland are benign; however most tumors arising from minor salivary glands are malignant.
The WHO lists at least 38 subtypes of epithelial tumors alone, as well as several stromal types. Regardless of this diversity, these tumors are rare; most of them occur in the major glands. The literature to date reports that the site of the tumors is distributed mainly between the parotid gland (about 80%) and submandibular gland (20%), while rarely are tumors found in the sublingual gland. Minor salivary gland tumors of the lips, oral cavity, pharynx, larynx, trachea, nasal mucosa, and paranasal sinuses are reported as uncommon. Nonepithelial salivary gland tumors were rare. Malignant tumors of the salivary glands are rare as compared to benign tumors. The most frequent benign tumor is pleomorphic adenoma followed by monomorphic adenomas. The most frequent malignant tumor of the parotid gland is mucoepidermoid carcinoma (50%), followed by adenoid cystic carcinoma (25%), carcinoma ex pleomorphica (15%), and acinic cell carcinoma (5%). Most studies worldwide report similar distribution., Contrarily, in our study, malignant tumors were found to be more common than benign tumors, probably because of the fact that ours is a tertiary care hospital amid many more private hospitals in a metropolitan city. In our study, the frequency of malignant tumors also increased with age after the third decade and the peak incidence of all patients with salivary gland tumors was in the fourth decade (47 years). Similar to our study, most other studies also have shown that salivary gland tumors are more common in males, but some studies have shown predominance in the female group.,,,
In the study by Spiro, the parotid gland was the most frequent site, representing 70% of the cases, followed by the minor salivary glands and the submandibular gland with 22% and 8% of tumors, respectively. All large series of salivary gland tumors showed similar results (Eveson and Cawson, 1985; Ellis and Auclair, 1996; Satko et al., 2000; and Ito et al., 2005).,, In our study also, parotid gland was found to be the most common gland with tumors. However, as mentioned previously, unlike most other reports where benign tumors were common, our study reported more of malignant tumors in parotid gland. Mucoepidermoid carcinoma was the most common malignant tumor and pleomorphic adenoma was the most common benign tumor of parotid gland. In general, 60% of people are estimated to have an accessory parotid gland which is normally not discovered unless a tumor is present, or as an incidental autopsy finding. Although the accessory parotid gland itself is common, tumors of this small organ are rare., Accessory parotid tumors have been reported to occur in 7.7% of overall parotid tumors, with a malignancy rate of 52%, though in some studies no malignancies have been reported., This incidence is comparatively higher than the standard incidence of malignancy in the parotid gland proper. However, in our experience, we could not encounter any case of either accessory salivary gland or its tumor. Klotz and Coniglio reported only four accessory parotid gland neoplasms over a 6-year period, all of which were benign pleomorphic adenomas. Lin et al. reported eight cases over a 10-year period, three of which had malignant disease.
According to literature, submandibular gland shows relatively equal distribution of benign and malignant tumors but more of malignant tumors than benign tumors in sublingual gland. The most frequent malignant tumor in submandibular gland has been reported to be adenoid cystic carcinomas (50%), followed by mucoepidermoid carcinomas (25%). However, in our study, majority of tumors of submandibular gland were malignant (mucoepidermoid carcinoma) than benign (pleomorphic adenoma). Eveson and Cawson also found that malignant tumors were more common in the submandibular and sublingual glands than in the parotid gland. Of 2410 tumors, they found only seven tumors in the sublingual gland and six of these were malignant. In some studies, no cases were found in the sublingual gland, confirming the low prevalence in this site., Eveson and Cawson found a ratio of one case of sublingual tumor to 100 parotid tumors. In contrast, Satko et al. reported sublingual tumors in 33 out of 1021 salivary gland tumors. In our study, tumors of sublingual gland were found in one patient only, and it was mucoepidermoid carcinoma.
Malignant tumors are more common in the minor salivary glands. Some authors in large series of salivary gland tumors have reported the incidence of malignant tumors in minor salivary glands ranging from 45% to 49%., The incidence of adenoid cystic carcinomas and mucoepidermoid carcinomas has been reported to account for 48% and 41.3% of all minor salivary tumors, respectively (Rivera-Bastidas et al., 1996; Lopes et al., 1999; and Jansisyanont et al., 2002).,, Some authors have reported that mucoepidermoid carcinomas is the most frequent malignancy of the minor salivary glands, accounting for 10%–15% of all salivary tumors., Very few series have focused solely on intraoral minor salivary gland tumors (Toida et al., 2005; Jaber, 2006; Pires et al., 2007; and Bianchi et al., 2008).,,, Pires et al. demonstrated that from a total of 546 minor salivary gland tumors, 55.9% were benign, the two most common tumors were pleomorphic adenomas (33.2%) and mucoepidermoid carcinomas (22.9%), and the most commonly affected site was the palate (33.2%). Toida et al., in a retrospective study, suggested that the minor salivary gland tumors in Japan may be characterized by a higher incidence of benign tumors, especially of pleomorphic adenomas, with a more marked tendency for female predominance, a higher incidence of palatal involvement, and a less common incidence of adenoid cystic carcinoma in comparison to those reported in the non-Japanese studies. In the studies from outside of Japan, it has been reported that the most common malignant minor salivary gland tumors are adenoid cystic carcinomas and mucoepidermoid carcinomas. In some large series of intraoral minor salivary gland tumors in 2007, Buchner et al. identified 380 tumors, of which 224 (59%) were benign and 156 (41%) were malignant. Of the benign tumors, pleomorphic adenomas were the most common (39.2%), and mucoepidermoid carcinomas were the most common malignant tumors (21.8%), followed by adenocarcinomas (7.1%) and adenoid cystic carcinomas (6.3%). In accordance with the literature concerning minor salivary gland tumors, the most common benign tumor was the pleomorphic adenoma, whereas the most common malignant tumor was either the mucoepidermoid carcinoma or adenoid cystic carcinoma.,, Comparing data from different studies, some discrepancies exist in the frequency and distribution of these tumors, which is possibly influenced by race and geographic location of the population in question. However, some reports in the literature are based on results from oral surgery institutions (predominantly minor salivary glands affected), while others are based on results from head-and-neck surgery (maxillofacial surgery/ENT) institutions; therefore, it is expected that the distribution of tumors is not necessarily in concordance. Also, due to extreme pathological diversity of salivary gland tumors, overlapping morphologies and recent change in nomenclatures, the interpretation of results may vary depending upon pathologist's interpretation., In this study, all the minor salivary gland tumors were malignant and mucoepidermoid carcinoma was the most common malignant tumor. In this study, we found a different occurrence rate of mucoepidermoid carcinoma of minor salivary glands depending on the location (i.e. 6.2% in the palate, 4.1% in the maxillary sinus, and 2% in lip, tongue, tonsil, soft palate, larynx each). Similar findings were observed in most published series., Some studies have reported that malignant tumors of the minor salivary glands are more common in males than females., However, other reports have indicated that this difference was not significant. In this study, minor salivary gland tumors were reported more commonly in females.
| Conclusion|| |
Our experience of 17 years has many similarities as well as dissimilarities with most large series on salivary gland tumors. The demographic and treatment data of salivary gland tumors presented herein can be helpful for a better understanding of both clinical and pathological characteristics of salivary gland tumors, including the geographic variations in the frequency and distribution of the disease in comparison with other similar published data.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]