|Year : 2020 | Volume
| Issue : 2 | Page : 178-181
Minor salivary gland mucoepidermoid carcinoma in an adolescent - A curious clinical presentation
MS Archana1, Anu Babu2, Geeta Sharma3
1 Department of Oral Medicine and Radiology, Geetanjali Dental and Research Institute, Udaipur, Rajasthan, India
2 Department of Oral Medicine and Radiology, Yenepoya Dental College, Deralakatte, Mangalore, Karnataka, India
3 Department of Oral and Maxillofacial Surgery, Geetanjali Dental and Research Institute, Udaipur, Rajasthan, India
|Date of Submission||15-Dec-2019|
|Date of Decision||01-Apr-2020|
|Date of Acceptance||19-Apr-2020|
|Date of Web Publication||27-Jun-2020|
Dr. Anu Babu
Department of Oral Medicine and Radiology, Yenepoya Dental College, Deralakatte, Mangalore, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Salivary gland tumors (SGTs) are classified as benign, malignant epithelial, soft tissue, hematolymphoid or secondary tumors. SGTs commonly affect the parotid gland and among the minor salivary glands, the hard palate is the commonest site as it harbors the highest number of salivary glands. According to various statistics, mucoepidermoid carcinoma (MEC) represents less than 0.5% of all the malignancies and less than 5% of malignant head and neck tumors. As the tumor can arise from different cells of excretory ducts these tumors often display a diverse biological behavior and unusual clinical presentation. We report a case of MEC which has a low incidence in adolescents with a rare clinical appearance.
Keywords: Diagnosis, mucoepidermoid carcinoma, palate, salivary gland tumor
|How to cite this article:|
Archana M S, Babu A, Sharma G. Minor salivary gland mucoepidermoid carcinoma in an adolescent - A curious clinical presentation. J Indian Acad Oral Med Radiol 2020;32:178-81
|How to cite this URL:|
Archana M S, Babu A, Sharma G. Minor salivary gland mucoepidermoid carcinoma in an adolescent - A curious clinical presentation. J Indian Acad Oral Med Radiol [serial online] 2020 [cited 2020 Jul 15];32:178-81. Available from: http://www.jiaomr.in/text.asp?2020/32/2/178/288130
| Introduction|| |
Salivary gland neoplasms are rare and constitute <1% of all the tumors and 6–8% of the head and neck cancer., Based on the type of gland affected they are classified as neoplasm affecting major salivary glands and minor salivary glands., Benign tumors affect parotid and submandibular glands whereas minor salivary glands are involved by malignant tumors.
Minor salivary gland tumors (SGTs) are a heterogeneous group of tumors with diverse histological types and growth patterns posing challenges in diagnosis. Ellis et al. Van der Laan et al., and Horn-Ross et al. emphasized the role of exposure to ionizing radiation, an occupational hazard in personnel working with rubber products or asbestos as risk factors in the development of these tumors.
Mucoepidermoid carcinoma (MEC) is regarded as a primary epithelial salivary gland malignancy affecting the elderly age group with no gender predilection. We present a unique case of an adolescent with a history of swelling for 8 days.
A male patient aged 19 years [Figure 1] reported with a swelling on the hard palate region which he first noticed eight days back and gradually increased in size [Figure 2]. History revealed bleeding from the gums while brushing. There was no positive history of pain, pus discharge, or bleeding from the swelling. Medical and personal history was negative. Associated lymph nodes were non-palpable. Intraoral examination revealed a well-defined swelling on the right half of hard palate about 3 × 3.5 cm anteriorly from the palatal rugae up to the palatal aspect of 18 regions. Mediolaterally it extended from the region of 14, 15, 16, 17, and 18 crossing the midline. The surface was lobulated with intact overlying mucosa and was mildly bluish in color [Figure 2]. On palpation, the swelling was soft to firm, non-tender, and mildly fluctuant. A provisional diagnosis of Minor SGT was considered with differential diagnosis such as palatal abscess, odontogenic cyst, necrotizing sialometaplasia, hemangioma, and benign mucosal tumor arising from the sinus.
|Figure 2: Clinical view showing palatal swelling with lobulated and bluish surface|
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14 and 15 were non-vital. The maxillary occlusal radiograph showed a hazy radiopacity obliterating the right nasal cavity [Figure 3]. A panoramic radiograph revealed an ill-defined radiolucency extending from the palatal root of 17 till the interdental area of 17 and 18. The floor of the right maxillary sinus appeared discontinuous from 15 to 18 regions. A well defined radiopaque shadow was seen over the apical third of the roots between 13 and 17 regions [Figure 4].
|Figure 3: True maxillary occlusal view showing hazy radiopacity over the right nasal cavity|
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|Figure 4: OPG showing bone loss IRT 17 extending till 18, discontinuity in the floor of the maxillary sinus, a radiopaque shadow from 13 to 17 regions|
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Plain and contrast computed Tomography (CT) axial section revealed hypodense expansile lesion measuring approximately 43 × 29 × 33 mm involving the right maxillary alveolus and sinus causing destruction of buccal and palatal cortical plates [Figure 5]a. The lesion extended till the posterior and lateral walls of the sinus. The coronal section showed an extension into the right nasal cavity [Figure 5]b. Sagittal section showed the lesion obliterating the right maxillary sinus [Figure 5]c. No cervical lymph node enlargement was noted.
|Figure 5: a-Axial view. Hypodense expansile lesion involving the right maxillary alveolus and sinus causing destruction of buccal and palatal cortical plates. b-Coronal view. Lesion extending into the nasal cavity. c-Sagittal view. Lesion extending up to the middle third of sinus cavity|
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Fine-needle aspiration biopsy (FNAB) revealed a thick mucus aspirate. On biopsy, a grayish brown soft tissue about 1.5 cm was acquired [Figure 6]. Microscopic examination showed fibro-vascular tissue with lobules of salivary gland tissue, focal areas of hemorrhage and neutrophilic exudates. Collapsed and distended cystic spaces filled with mucinous material lined by mucous cells, intermediate cells and epidermoid cells. Nuclear atypia and mitosis were infrequent [Figure 7]a and [Figure 7]b. These findings suggested a low-grade type of MEC. The final diagnosis of low-grade MEC arising from the palatal minor salivary gland was considered. A total maxillectomy of the right side was performed and reconstruction was done with vascularized osteocutaneous free fibula flap.
|Figure 7: a—Photomicrographs illustrates low-grade mucoepidermoid carcinoma showing ductal and cystic spaces surrounded by mucous and epidermoid cells (Original magnification × 20). b—Photomicrograph illustrates pale staining mucous cells with darker staining epidermoid cells and many intermediate cells around central cystic space (Original magnification × 40)|
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| Discussion|| |
Masso and Berger in 1924 first reported MEC. World Health Organization defines MEC as “A malignant glandular epithelial neoplasm characterized by mucous, intermediate and epidermoid cells, with columnar, clear cell and oncocytic features.” MEC mostly affects patients with a mean age of 45 years with no gender predilection. This was in contrast to the present case and the cases reported by Rawson et al. where the age of the patients was 19 and 9 years, respectively.
The parotid gland is most commonly affected. Among the minor salivary glands, the palate is commonly involved. The retromolar area, buccal mucosa, tongue, lips, and floor of the mouth are other frequent sites. It is also known to arise from salivary—type glands in sinonasal and laryngeal mucosa, lacrimal, and ceruminous glands and even nodular inclusions arising from the thyroid gland.
MEC presents as a painless fixed rubbery or soft swelling appearing blue-red tinged due to its superficial location mimicking vascular lesion or mucocele. Occasionally ulceration, pain, paresthesia, fluctuation, and bone erosion due to pressure effects may be present. In the present case, the patient presented with a bluish tinged swelling with soft and fluctuant areas and an intact overlying mucosa in contrast to the case reported with ulceration by Rawson et al.
The differential diagnosis for unilateral palatal swelling includes Squamous cell carcinoma, Benign minor SGT, that is, pleomorphic adenoma, the early stage of necrotizing sialometaplasia, hemangioma, a benign mucosal tumor arising from maxillary sinus lining and malignant melanoma.
Studies have shown that high-frequency intraoral USG has better spatial resolution than CT and magnetic resonance imaging (MRI). USG guided FNAC with local anesthesia can help in avoiding complex surgical procedures. In a case series by Rawson et al. The author reported a case of intermediate MEC which showed negative aspiration which was in contrast to the present case.
CT features are not pathognomonic although aggressive bone destruction and infiltrative invasive pattern can be appreciated. MRI is useful in assessing the soft-tissue characteristics, enhancement pattern, submucosal extension and perineural spread. MEC shows a propensity to spread perineurally. T2W Imaging shows the hypointense mass and perineural spread correlating to the high cellularity of the tumor. Recent studies have shown that 18-fluorodeoxyglucose-positron emission tomography-CT has advantages in loco-regionally advanced tumors.
Klinjanienko et al. reviewed FNAB and histological correlation and concluded  that 87% of high-grade tumors showed accurate diagnosis compared to low-grade tumors. Another study concluded that the interpretation of FNAB is greatly influenced by the experience of the pathologist.
Histopathological examination is regarded as the gold standard for diagnosis. Macroscopically it appears well-circumscribed, lobulated, none encapsulated, rubbery, solid white, grey or tan areas with cystic areas containing viscous material based on the grade of the tumor. [Table 1] illustrates the histological grading used in MEC.
Genomic alterations and markers were studied in MEC. Tonon et al. reported translocation t (11; 19) (q14-21;p12-13) which results in a fusion between exons 1 and 2 of CRTC1 on chromosome 19p13 and MAML2 on chromosome 11q21 (a member of the mastermind-like gene family) disrupting the NOTCH signaling pathway. Immunohistochemistry studies have shown a positive correlation in the expression of proliferation marker Ki-67 with the increased histological grade. Ado Rabo et al. study showed that p63 was strongly expressed in these tumors.
Complete surgical resection remains the mainstay of treatment. High-grade tumors mandatorily need elective neck dissection; however low and intermediate grades have low nodal metastasis. Micro-marsupialization, cryosurgery, and laser therapy are contraindicated in children and adolescents as it can result in the local spread of the tumor and require aggressive surgery. Although SGTs are radio resistant, radiotherapy is indicated in positive/unclear surgical margins, nodal involvement and high-grade tumors. Adjuvant chemotherapeutic drugs namely cisplatin, cyclophosphamide, and doxorubicin are under trials for high-grade tumors.
The prognosis of MEC is dependent on histological grading. Low and intermediate-grade tumors have a favorable prognosis with a low recurrence rate (<10%) and a high survival rate (95–100%). High-grade tumors have a poor prognosis with a reduced survival rate.
| Conclusion|| |
In comparison to the high-grade MEC, low-grade tumors have a favorable outcome. Important prognostic factors namely gland type, histology, grade, stage, facial nerve involvement, fixation, and spread to the distant areas mark the treatment outcome.
When palatal swellings of shorter duration are encountered at a younger age it is of primary importance to identify the origin of the lesion with most apt imaging techniques combined with incisional/excisional biopsy so that an early diagnosis could be done which will help in minimizing the extent of surgical excision. Treatment depends on the grade of the tumor and nodal involvement. A regular and prolonged period of follow up is required to avoid recurrence.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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