Abstract
Background
Pleomorphic adenoma is the most common salivary gland tumor affecting both major and minor glands. It has different clinical presentations and histological patterns. Outcome of pleomorphic adenoma varies widely with the risk of recurrence, malignant transformation and facial nerve involvement being the most important aspects among other postoperative complications.
Objectives
To study the clinicopathological features of pleomorphic adenoma, its distribution in head and neck region and evaluation of outcomes of surgical treatment in terms of tumor recurrence and other postoperative complications.
Methodology
Retrospective analytical hospital–based study of all records of patients diagnosed with pleomorphic adenoma of salivary glands who attended Khartoum Teaching Dental Hospital (KTDH) during period from 2007 to 2021. Data was analyzed using the Statistical Package for Social Sciences (SPSS) version 27. Chi square test to assess associations. Linear regression, binary logistic regression & cox regression multivariate analysis to estimate the significance and relations.
Results
Two hundred fifteen patients fulfilled the inclusion criteria. Pleomorphic adenoma was found to be more common in females, in the fourth decade of life affecting the right side more commonly. Minor glands were affected more commonly with the palate being the most common site followed by the parotid. Definitive histopathological assessment revealed 201 (93.5%) pleomorphic adenoma with classic subtype being the most common, while 14 (6.5%) were carcinoma arising within pleomorphic adenoma. Post operative complications occurred in 72(33%) with facial nerve injury and oroantral fistula being the most commonly encountered. Recurrence was observed in 15 (7%) and malignant transformation in 3 cases (1.4%).
Conclusion
Although pleomorphic adenoma is a benign salivary gland neoplasm, it can grow into extensive size if left untreated causing disfigurement and may undergo malignant transformation thus need to be diagnosed early and complete excision of the tumor is the definitive treatment to prevent tumor recurrence. Meticulous dissection of facial nerve during parotid operation and use of SMAS layer flap is also recommended so as to prevent facial nerve damage and occurrence of Frey syndrome. Long-term follow up of pleomorphic adenoma is required to assess the risk of recurrence and malignant transformation as they usually occur over a long duration.
Keywords: Pleomorphic adenoma, Complications, Clinical outcome, Recurrence, Malignant transformation
Introduction
Pleomorphic adenoma (PA) is the most common salivary gland tumor in children and adults [1] affecting both major and minor salivary glands, accounting for 40–70% of all salivary gland tumors, and originates mainly in the parotid gland [2].
Tumors arising from the minor salivary glands are rare clinical entities, accounting for 10–25% of all salivary gland tumors [3].
Pleomorphic adenomas can occur at any age, but mainly affect patients in their fourth, fifth and sixth decades of life. 60% of them are females, and 40% males [4].
Pleomorphic adenoma can be defined as a benign mixed tumor characterized pathologically by neoplastic proliferation composed of epithelial, myoepithelial, and stromal components arranged with various morphological patterns, delimited from the surrounding tissues by fibrous capsule [2, 5].
Ablative surgery is the therapy of choice [6]. Simple enucleation of this tumor is thought to lead to a high rate of local recurrence and should be avoided [7]. Capsular rupture or tumor spillage is also thought to increase the risk of recurrence, so careful dissection is paramount. Prognosis is excellent with a 95% cure rate. The tumor is radio resistant, so radiotherapy is not indicated [8].
Recurrences after primary surgery are difficult to be treated and several recurrences should be expected during the long-term follow-up [9, 10]. Recurrence of PA after surgery has been reported in 0.5% to 10%, increasing to 48% in some reports if treated by enucleation [10–12].
Pleomorphic adenoma can give rise to malignant tumors, especially carcinoma. The risk of malignant transformation of PA increases with the duration of the lesion [13] and is reported to be 3–4% [10].
In sudan, no previous study has investigated the prevalence, clinical presentation and histological variations of pleomorphic adenoma of salivary glands. For this reason, the present study was the largest study in Sudan conducted for better understanding about the diversity of this tumour and set out also to assess the different surgical treatment modalities and outcomes of pleomorphic adenoma of salivary glands so as to assist in better diagnosis and treatment outcome and better prediction of prognosis.
Materials and methods
This is a retrospective analytical hospital – based study conducted at Khartoum Teaching Dental Hospital - OMFS department. Laboratory results were obtained from oral pathology laboratory department/ university of Khartoum, National public health laboratory (STACK), and Prof. Ali Abdelsatir histopathology lab.
This study examined the complete records (total coverage) of all patients diagnosed with pleomorphic adenoma of salivary glands who attended KTDH betweem 2007 and 2021. Inclusion criteria involved all patients who were diagnosed and surgically treated for pleomorphic adenoma of salivary glands at that period. While patients diagnosed with a recurrent lesion at their initial hospital presentation, those with co-existing lesions or malignancies, and cases with incomplete reports were excluded from the study.
Data collection was carried out by using data collection sheet, which was constructed by comprehensive review of literature and filled by the researcher from the patient’s file record. Further communication with patients was achieved.
Processing, analysis and presentation of data
Data was analyzed using the Statistical Package for Social Sciences (SPSS) version 27. Descriptive statistics in terms of frequency tables with percentages and graphs. Chi square test to assess associations (P- value of 0.05 or less was considered significant). Linear regression, binary logistic regression & cox regression multivariate analysis to estimate the significance and relations.
Data were represented after analysis in forms of univariable tables, bi-variable tables (cross tabulations), multivariable tables and figures.
Results
215 were enrolled in the study. 127 were females (59%) (Fig. 1).
Fig. 1.
Shows the gender distribution
Age distribution
The age of patients ranged from 12 to 80 years with the majority (67%) in their third, fourth and fifth decades of life. The most common age group was 30–39 years accounting for 25% of cases. Only 21 cases (9.8%) were less than 20 years and 10 cases (4.7%) were above 70 years old (Fig.2). Mean age was 38 ± 15 years.
Fig. 2.
Shows age distribution
Side of tumor
Most tumors 117 (54.8%) were found to be located on the right side.
Site distribution
Minor glands were involved in 122 cases (57%), major glands in 92 cases (43%) and one case (0.5%) in heterotropic site (Fig. 3).
Fig. 3.
Site of the lesion (details)
Surgical modality
The main surgical modality was excision with safety margins in 121 (56%), Submandibular gland excision was done in 40 (18.6%), and complete superficial parotidectomy in 26 (12%). Neck dissection was done in 5 (2.3%). (Table 1).
Table 1.
Surgical modality
| Frequency | Percent | |
|---|---|---|
| Excision with safety margins | 121 | 56% |
| Enucleation | 2 | 0.9% |
| Submandibular gland excision | 40 | 18.6% |
| Sublingual gland excision | 3 | 1.4% |
| Extracapsular dissection | 12 | 5.5% |
| Complete Superficial parotidectomy | 26 | 12% |
| Partial superficial parotidectomy | 6 | 2.8% |
| Total parotidectomy | 4 | 1.8% |
| Deep lobe parotidectomy | 1 | 0.5% |
| Debulking | 1 | 0.5% |
| Neck dissection | 5 | 2.3% |
Facial nerve was preserved in 79 (88.7%), sacrificed in 7 (7.9%), and cut and re-anastomosed in 3 (3.4%). Skin was sacrificed in 4 (5%), and overlying mucosa was sacrificed in 112 (90%). Bone management for maxilla and palate was done in 22 (20.6%) mainly in form of peripheral ostectomy in 12 (54.5%), reconstruction was done for 12 (5.6%). Adjuvant therapy was indicated in 9 (4.2%) for reason of malignancy (Table 2).
Table 2.
Operation and management
| Frequency | Percent | |
|---|---|---|
| Facial nerve | 89 | |
| Preserved | 79 | 88.7% |
| Partially sacrificed | 4 | 4.5% |
| Totally sacrificed | 3 | 3.4% |
| Cut and re-anastomosed | 3 | 3.4% |
| Overlying skin | 90 | |
| Preserved | 86 | 95.6% |
| Sacrificed | 4 | 4.4% |
| Overlying mucosa | 125 | |
| Preserved | 13 | 10.4% |
| Sacrificed | 112 | 89.6% |
| Bone management | 22 | 10.2% |
| peripheral ostectomy | 12 | 54.5% |
| class 1 maxillectomy | 1 | 4.5% |
| class 2a maxillectomy | 7 | 31.8% |
| class 3a maxillectomy | 1 | 4.5% |
| marginal mandibular resection | 1 | 4.5% |
| Reconstruction | 12 | 5.6% |
| Adjuvant therapy | 9 | 4.2% |
| Concurrent | 4 | 1.9% |
| Radiotherapy | 5 | 2.3% |
Definitive diagnosis
Definitive diagnosis was pleomorphic adenoma in 201 (93.5%), which was of classic histopathological subtype in 77.6%, clear pathological margins were achieved in 76.3%, total encapsulation of tumor was found in 45.3%, multiple nodules were present in 8.5%. Carcinoma ex pleomorphic adenoma was diagnosed in 10 (4.6%) (Table 3).
Table 3.
Definitive diagnosis
| Frequency | Percent | site | |
|---|---|---|---|
| Carcinoma ex pleomorphic adenoma | 10 | 4.6% |
Parotid gland = 5 Submandibular gland = 1 Sublingual gland = 1 palate = 3 |
| Adenocarcinoma | 2 | 0.9% |
Parotid gland = 1 Palate = 1 |
| Salivary duct carcinoma | 1 | 0.5% | Parotid |
| Clear cell carcinoma | 1 | 0.5% | palate |
| Pleomorphic adenoma : | 201 | 93.5% | |
| Histopathological subtype | |||
| Classic | 156 | 77.6% | |
| Myxoid | 25 | 12.4% | |
| Cellular | 20 | 10% | |
| Encapsulation | |||
| Total encapsulated | 91 | 45.3% | |
| Partial encapsulated | 82 | 40.8% | |
| Not encapsulated | 28 | 13.9% | |
| Multiple nodules | |||
| No | 184 | 91.5% | |
| Yes | 17 | 8.5% | |
| Pathological margins | 215 | ||
| Clear | 164 | 76.3% | |
| Closed | 11 | 5.1% | |
| Involved | 34 | 15.8% | |
| Cannot be assessed | 6 | 2.8% |
Follow-up and complications
Follow up period after surgical removal of tumor ranged from at least 1 year to 15 years. The median follow-up time was 7 + SD years. Complications occurred in 72 cases (33%) including facial nerve injury 30.3% of parotid and submandibular surgery, Frey syndrome 16%, oroantral fistula 20.6%, salivary fistula 10%, and lingual nerve injury 5.1%. Recurrence occurred in 7% and malignant transformation in 1.4% (Table 4). Patients underwent complete superficial parotidectomy experienced higher incidence of Facial nerve injury (65.4%), impaired sensation (27%), frey syndrome (23%) and salivary fistula (11.5%) while extracapsular dissection showed higher incidence of recurrence (16.7%) (Table 5).
Table 4.
Complications
| Frequency | Total number | Percent | |
|---|---|---|---|
| Nerve injury | |||
| 1) Facial | 27 | 89* | 30.3% |
| Temporary paresis | 19 | 70.4% | |
| Permanent paresis | 8 | 29.6% | |
| Partial paresis | 20 | 74% | |
| Complete paresis | 7 | 26% | |
| 2) Lingual | 2 | 42** | 4.7% |
| 3) Hypoglossal | 0 | 0% | |
| 4) Greater auricular | 10 | 50*** | 20% |
| Frey syndrome | 8 | 50 | 16% |
| Oroantral fistula | 22 | 107 | 20.6% |
| Salivary fistula | 5 | 50 | 10% |
| Recurrence | 15 | 215 | 7% |
| Malignant transformation | 3 | 215 | 1.4% |
| Other complications (infection, hematoma, impaired speech) | 26 | 215 | 12% |
* representing those of parotid and submandibular lesions
** representing those of sublingual and submandibular lesions
*** representing those of parotid lesions
Table 5.
Comparison between different parotid surgeries and their associated complications
| Complication | Extracapsular dissection (n = 12) |
Partial Superficial Parotidectomy (n = 6) |
Complete Superficial Parotidectomy (n = 26) |
Total Parotidectomy (n = 4) |
||||
|---|---|---|---|---|---|---|---|---|
| n | % | N | % | n | % | n | % | |
| Facial nerve injury | 1 | 8.3% | 1 | 16.6% | 17 | 65.4% | 2 | 50% |
| Impaired sensation | 2 | 16.7% | 1 | 16.6% | 7 | 27% | 0 | 0% |
| Frey syndrome | 2 | 16.7% | 0 | 0% | 6 | 23% | 0 | 0% |
| Salivary fistula | 1 | 8.3% | 0 | 0% | 3 | 11.5% | 0 | 0% |
| Recurrence | 2 | 16.7% | 1 | 16.6% | 3 | 11.5% | 0 | 0% |
Mortality rate
Mortality rate was 6% (Fig. 4).
Fig. 4.
Outcome
Survival
The overall survival in 15 year duration was 96.7%. Survival of patients with recurrence was 85.3%. Survival of patients with malignant transformation was 84.4% (Table 6).
Table 6.
15 years survival
| Survival % (estimated) | |
|---|---|
| Overall | 96.7% (14.5) |
| Recurrence : | |
| No | 97.6% (14.65) |
| Yes | 85.3% (12.8) |
| Malignant transformation : | |
| No | 96.9% (14.55) |
| Yes | 84.4% (12.67) |
Risk factors for recurrence
Multivariate logistic regression analysis of factors associated with recurrence was significant for snuff dipping (6 times) (p-value 0.04), tumor size, closed margins and the presence of multiple nodules (Table 7).
Risk factors for malignant transformation
No factor was significantly associated with malignant transformation (Table 8).
Table 7.
Multivariate logistic regression for risk factors of recurrence
| Odds ratio | p-value | |
|---|---|---|
| Age | 1.1 | 0.8 |
| Gender | 1 | 0.4 |
| Comorbidities | 1.8 | 0.3 |
| Smoking | 0 | 0.9 |
| Snuff dipping | 7 | 0.04* |
| Alcohol consumption | 0 | 0.9 |
| Tumor size | -0.02 | 0.001* |
| Tumor site | 1.5 | 0.3 |
| Histological subtype: | ||
| Classical subtype | 2.8 | 0.2 |
| Cellular subtype | 0.8 | 0.9 |
| Myxoid subtype | 0.6 | 0.5 |
| Capsule status: | ||
| Not encapsulated | - | 0.9 |
| Partial encapsulation | - | 0.9 |
| Total encapsulation | - | 0.9 |
| Margins : | ||
| Clear | 0.2 | 0.2 |
| Close | 0.007 | 0.001* |
| Involved | 0.1 | 0.1 |
| Multiple nodules : | ||
| Absent | 0.1 | 0.1 |
| Present | 0.1 | 0.001* |
| Surgical technique (all) | - | 0.9 |
*significant P-value less than 0.05
(-) means that P value is too high that odds ratio can not be calculated
Table 8.
Multivariate logistic regression for risk factors for malignant transformation
| Odds ratio | p-value | |
|---|---|---|
| Age | 1.1 | 0.9 |
| Gender | 0.9 | 0.8 |
| Comorbidities | 2.4 | 0.4 |
| Smoking | 0 | 0.9 |
| Snuff dipping | 0 | 0.9 |
| Alcohol consumption | 0.8 | 0.9 |
| Tumor size | 1 | 0.3 |
| Tumor site | 2 | 0.4 |
| Histopathological subtype: | ||
| Classical | - | 0.6 |
| Cellular | - | 0.9 |
| Myxoid | - | 0.9 |
| Capsule status: | ||
| Not encapsulated | - | 1 |
| Partial encapsulation | - | 0.9 |
| Total encapsulation | - | 0.9 |
| Margins : | ||
| Clear | - | 0.9 |
| Close | - | 0.9 |
| Involved | - | 0.9 |
| Multiple nodules : | ||
| Absent | 0 | 0.3 |
| Present | 0.1 | 0.9 |
| Surgical technique (all) | 1 | 0.9 |
Discussion
The present study showed female predominance (59%), which supports the observation of most authors in literature ; Reinhard et al. [14], Moon et al. [15], Orlando et al. [16], Pedro et al. [17], Janusz et al. [18], Barca et al. [19], Nedim et al. [20], Honghai et al. [21], and Simon et al. [22], but in contrast to Suhail et al. [23], Yen kuo et al. [24], Natasha et al. [25] and Jong-lyel et al. [26] in which they found a male predilection. Some authors had hypothesized that tumors are hormone-dependent; Glas et al. [27] studied the effect of sex hormones, insulin-like growth factor receptor 1 and the Ki-67 antigen (a pleomorphic adenoma cell proliferation marker) in pleomorphic adenoma. They observed a higher prevalence of tumors with receptors for progesterone and insulin-like growth factor 1 in patients with multiple recurrences.
Age of patients ranged from 12 to 80 years with most of cases (67%) were found to be in their third, fourth and fifth decades, with a mean age of 38 ± 15 years, this is a lower finding compared to Reinhard et al. study in which they found the mean age was 57.6 years [14], 55 year in Orlando et al. [16], 48 year in Pedro et al. [17] and Jong-lyel et al. [26], and 44.14 year in Suhail et al. study [23]. This earlier presentation and diagnosis may be attributed to the increased esthetic and functional concern among females which were the predominate gender in the present study.
Fifty –five% of cases were found to be located on the right side, this finding is similar to previous studies done by Reinhard et al. [14], Pedro et al. [17], Janusz et al. [18], Natasha et al. [25] and Jong-lyel [26] in which they found right side predominance, while left side predominance was reported only by Orlando [16].
Minor glands were involved more common (57%) than major glands (43%) with the palate being the most commonly involved site (49.8%) due to greater concentration of salivary glands in this location compared to other minor salivary glands, followed by its occurrence in the parotid gland (23%) and submandibular gland (18%). This is in contrast to literature; Reinhard et al. [14], Honghai et al. [21] and Natasha et al. [25] which revealed parotid gland tumor predominance. The lower percentage of parotid gland tumors may be attributed to community level of awareness for seeking care and treatment of non oral lesions in other specialties like general surgery, ENT and plastic surgery departments rather than oral and maxillofacial surgery department.
Provisional diagnosis was mainly pleomorphic adenoma (208/215; 97%). All cases were surgically treated. Neck dissection was carried out in 5 cases in which provisional diagnosis indicated malignancy or in cases with neck positive nodes. Bone management was done in 22 cases (10.2%) and reconstruction was considered for 12 cases (5.6%).
Definitive diagnosis of submitted specimens revealed: 201 pleomorphic adenoma (93.5%), 10 carcinoma ex pleomorphic adenoma (4.6%), 2 adenocarcinoma arising from pleomorphic adenoma (0.9%), 1 clear cell carcinoma arising from pleomorphic adenoma (0.5%), and 1 salivary duct carcinoma with clear cell differentiation ex pleomorphic adenoma (0.5%).
Regarding histopathological subtypes of pleomorphic adenoma, classic subtype was found predominantely in 156 (77.6%), followed by myxoid subtype 25 (12.4%), the cellular subtype was the least common accounting for 20 (10%). In agreement with Yen Kuo et al. [24] who found classic subtype accounting for 89.2% and cellular subtype accounting for 10.8%, no myxoid subtype was found in their study. Nedim et al. [20] also revealed classic subtype predominates with 58.9% followed by myxoid (29.9%) and then cellular subtypes (11.7%). Honghai et al. [21] also found the classic subtype in 43.3% of cases submitted in their study, followed by cellular (40%) and then myxoid subtype came last (16.7%).
The tumor was totally encapsulated in 91 cases (45.3%), partially encapsulated in 82 (40.8%), and capsule was not present in 28 (13.9%). Comparing this result with Yen kuo et al. study [24], they similarly found total encapsulation predominates (70.3%), but loss of capsulation comes second (18.9%), the rest were partially encapsulated (10.8%). Multiple nodules were evident in 17 pathological specimens (8.5%).
Postoperative complications were present in 72 cases (33%), this correlates with Orlando et al. [16] findings of 36.2% complications, but disagree with Barca et al. [19] study where only 18.4% complication rate had been present.
Facial nerve injury following parotid or submandibular gland surgery accounted for 30.3% (27/89), this is relevant to that mentioned by Natasha et al. (37.5%) [25], while in Pedro et al. study [17] it accounts for 77.2%, and only 19.5% was recorded by Nedim et al. [20]. The lowest occurrence (5.6%) was reported by Jong-lyel et al. [26]. Partial paresis occurred in 20 cases (22.5%), this correlates with Orlando et al. findings 24% [16]. Marginal mandibular branch was affected more commonly (15.7%), as mentioned also by Pedro et al. [17], followed by buccal branch (12.4%), zygomatic (9%), and temporal (2.2%). Complete paresis seen in 7 cases (7.8%), and this is slightly higher than that reported by Orlando (3%) [16]. Most of paresis were temporary 19 (21.3%) that resolved over a period ranging from 1 month to 2 years, this finding considered higher than that found in Janusz et al. study (10%) [18]. Other 8 cases unfortunately developed permanent paresis (9%), this correlates with Janusz et al. finding (8%) [18], but a lower percent was reported by Orlando et al. (5%) [16].
Impaired sensation over skin of parotid and auricle occurred in 20% (10/50) this is considered a lower percent compared to Pedro et al. (84.9%) [17] and Jong-lyel et al. (31.5%) [26].
Frey syndrome occurred in only 16% (8/50), this fortunately may be due to the preparation and repositioning at the end of surgery of the border of SMAS (Superficial Muscular Aponeurotic System). Orlando et al. [16] found this complication approaching 63%, while in Pedro et al. study 11.4% [17], with the least recordings by Natasha et al. and Jong-lyel et al. (2.4%) [25, 26].
Regarding recurrence, it occurred in 15 cases (7%) compared to 19% in Reinhard et al. [14], 5.6% in Moon et al. [15], 8.1% in Yen kuo et al. [24], 0.6% in Orlando et al. [16], 8.2% in Janusz et al. [18], 3% in Barca et al. [19], 36.4% in Nedim et al. [20], 4.9% in Natasha et al. [25], and 2.86% in Simon et al. study [22].
Seven of the recurred tumors were palatal tumors, 6 were parotid tumors (all of them located on superficial lobe), 1 submandibular, and 1 sublingual tumor. Size of all tumors was equal to 50 mm and more. Thirteen tumors showed involved margins and 2 ruptured during operation and seeding occurred. Interestingly, one of the recurred tumors occurred simultaneously with pregnancy 3 months after operation. Secondary recurrence observed in one patient of submandibular gland and later treated by surgical excision and adjuvant radiation therapy due to multiple recurrences and positive pathological margins. A tertiary recurrence was seen in one patient of hard and soft palate, the recurrence was observed 1 year after operation and was due to involved margins and the patient was treated by surgical excision only. One recurrent case involved a patient who experienced recurrence six months after parotid surgery and passed away one year later due to tumor progression, before a secondary surgery could be performed. All other recurrent cases were managed successfully with surgical excision alone. Malignant transformation occurred in 3 cases (1.4%) on recurrent pleomorphic adenoma while 14 cases were diagnosed as de novo carcinoma (6.5%). Reinhard et al. [14] reported 8.5% malignant transformation while Moon et al. [15] reported the incidence to be 5.6%, Yen kuo et al. 2.7% [24], and Simon et al. 2.1% (84% of them arised de novo) [22]. One case of malignant transformation occurred in palate 9 years after operation as low grade adenocarcinoma, features suggesting malignancy were development of pain and rapidly growing swelling associated with epiphora. TNM stage was T4N1Mx.
The second case of malignant transformation was diagnosed as adenoid cystic carcinoma of submandibular gland occurred 4 years after operation, and was referred for concurrent chemo-radiotherapy due to lung matastasis confirmed by chest CT scan. The TNM stage was T3N1M1. Unfortunately, the patient died 8 years from primary operation as a result of lung metastasis and chemotherapy effects.
The third malignant case was diagnosed as adenoid cystic carcinoma of sublingual gland (T3N1Mx) 3 years later, presenting with pain and swelling in floor of the mouth, and treated by surgical excision with marginal mandibular resection and neck dissection.
Seven of the 14 cases of de novo diagnosed malignancy were diagnosed from provisional diagnosis (ca. ex pleomorphic adenoma 3, clear cell carcinoma 2, acinic cell carcinoma 1, mucoepidermoid carcinoma 1) while others were diagnosed after complete surgical excision (ca. ex pleomorphic adenoma 5, adenocarcinoma arising within pleomorphic adenoma 2). Eleven cases were of total lesion duration of more than 10 years, and the remaining 3 cases were of 6- year duration only. Adjuvant therapy was indicated for 9 cases as radiotherapy for 5 cases (2.3%) and concurrent chemo-radiotherapy for 4 cases (1.9%). The overall mortality rate was 6% (12 cases; 4 were due to disease progression, 2 due to complications of chemotherapy, 1 due to lung mets, and 5 due to unrelated factors).
Limitations of the study: missing data or records of patients
The authors recommended to increase the level of awareness among general population and medical staff, so as tumors of major salivary glands especially those of parotid and submandibular glands are within the scope of oral and maxillofacial surgery.
Meticulous dissection of facial nerve during parotid operation and use of SMAS layer flap is also recommended so as to prevent facial nerve damage and occurrence of Frey syndrome. Long-term follow up of pleomorphic adenoma is required to assess the risk of recurrence and malignant transformation as they usually occur over a long duration. Further prospective studies and molecular analysis of pleomorphic adenoma in future researches to be carried out to improve diagnosis and treatment strategies in form of : identifying biomarkers that can predict the clinical behavior, molecular mechanisms of malignant transformation through specific molecular events and mutations, implementing a better imaging technique like MRI to aid in better diagnosis and predict prognosis, exploring targeted drug therapy especially for inoperable or aggressive tumors to achieve better treatment, and larger long term studies needed to better understand the outcome.
Conclusion
Pleomorphic adenoma is a benign salivary gland tumor that occurred most commonly among females in the third, fourth and fifth decades of life. Minor salivary glands were affected more commonly with the palatal region being the most commonly affected site. Painless swelling was the major presentation, which can grow into an extensive size and may erode bone if left untreated. Surgical treatment modality depends on site and extent of the lesion, for palatal tumors, excision with safety margin was done and most parotid tumors underwent superficial parotidectomy.
Temporary partial facial nerve weakness was the most common complication among parotid surgeries while oroantral fistula was the commonest after palatal tumor excision.
Recurrence was found in the palate more commonly and was associated with snuff dipping, tumor size, closed margins and the presence of multiple nodules in histological specimen, while malignant transformation was found in parotid more commonly and no associated risk factors had been related.
Thus, pleomorphic adenoma of salivary glands need to be diagnosed early because it may undergo malignant transformation, and complete excision of the tumor is the definitive treatment to prevent tumor recurrence and long-term follow up is required.
Acknowledgements
Not applicable.
Authors’ contributions
Ta.Os: Manuscript writer, collected and analyzed the data, reviewed and finalized the manuscript.Yo. El: Supervisor, created the concept, reviewed, and finalized the manuscript.Yo. Os: Supervisor, reviewed, and finalized the manuscript. -All authors have read and approved the manuscript.
Funding
No funding was obtained for this study.
Data availability
The datasets used and/or analysed during the current study are available from the corresponding author upon reasonable request.
Declarations
Ethical approval and consent to participate
Ethics in accordance with declaration of Helsinki.
All authors hereby declare that all cases have been examined and approved by the appropriate ethics committee of the Sudan Medical Specialization Board, and the Federal Ministry of Health in Sudan. Informed consent was obtained from all the patients.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analysed during the current study are available from the corresponding author upon reasonable request.