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 Table of Contents  
Year : 2018  |  Volume : 30  |  Issue : 2  |  Page : 161-164

Mucoepidermoid carcinoma at an uncommon location

1 Department of Oral Medicine and Radiology, AJ Institute of Dental Sciences, Mangalore, Karnataka, India
2 Department of Oral and Maxillofacial Surgery, AJ Institute of Dental Sciences, Mangalore, Karnataka, India

Date of Submission16-Sep-2017
Date of Acceptance17-Feb-2018
Date of Web Publication16-Jul-2018

Correspondence Address:
Dr. Reshma Suvarna
Department of Oral Medicine and Radiology, AJ Institute of Dental Sciences, Kuntikana, Mangalore - 575 004, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jiaomr.jiaomr_86_17

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Mucoepidermoid carcinoma (MEC) usually arises from salivary glands, representing 5–10% of all salivary gland tumors, and rarely arises in the jaws. MEC mainly occurs in the parotid gland; intraorally MEC appears as asymptomatic swellings in minor salivary glands, mostly on the palate, and contributes for 2.8–15% of all salivary gland tumors. Due to its great biological diversity, treatment and prognosis depend on the histological grade, location, and tumor stage. Here, we present a case of MEC in a female patient aged 65 years with emphasis on the importance of early diagnosis and proper management of the disease. Even when its clinical appearance is not suggestive of malignancy, the diagnosis of MEC should be considered in cases of proliferative oral lesions.

Keywords: Minor salivary gland tumor, mucoepidermoid carcinoma, retromolar region

How to cite this article:
Suvarna R, Sorake S, Vachhani D, Boricha V, Rao PK, Kini R, Bhandarkar GP, Kashyap RR, Shetty D. Mucoepidermoid carcinoma at an uncommon location. J Indian Acad Oral Med Radiol 2018;30:161-4

How to cite this URL:
Suvarna R, Sorake S, Vachhani D, Boricha V, Rao PK, Kini R, Bhandarkar GP, Kashyap RR, Shetty D. Mucoepidermoid carcinoma at an uncommon location. J Indian Acad Oral Med Radiol [serial online] 2018 [cited 2023 Jan 28];30:161-4. Available from: http://www.jiaomr.in/text.asp?2018/30/2/161/236739

   Introduction Top

Mucoepidermoid carcinoma (MEC) is a very common malignant salivary gland tumor, which is composed of a mixture of cells, including mucus-producing, epidermoid or squamous and intermediate types.[1] The mean age of occurrence of MEC is 44.5 years.[2] MEC is mostly seen in the parotid gland for about 44.1%, and upto 25% in the minor salivary glands. Low, intermediate, and high-grade neoplasms accounted for 61.7%, 26.5%, and 11.8% of tumors, respectively.[3] MEC shows a wide range of biological behaviors, and the high-grade MEC is an highly aggressive tumor, while low-grade counterpart shows a more benign nature. The main treatment of MEC, like in most types of salivary gland malignancies, is surgical resection, and postoperative radiotherapy.[1] The size of the salivary gland is indirectly proportional to the incidence of malignancy of that gland. The smaller glands present increased risk of malignancy.[4] The gross appearance varies with the grade of the tumor. The main therapeutic method in the treatment of MEC, is surgical resection and postoperative radiotherapy seems to be efficient.[4]

   Case Report Top

A 65-year-old female patient reported to the department of Oral Medicine and Radiology with the chief complaint of pain and swelling in the lower left back tooth region since few years. The patient had noticed redness over the area, 5 years back and related to her newly fabricated upper denture contacting the surface since then. The lesion was slowly progressive from peanut size to the present size, associated with pain. Pain was gradual in onset, continuous, moderate in intensity, which aggravated on chewing food and relieved on taking medications (pain killers). A known hypertensive, under medication from 8 years. Extra oral examination revealed no facial asymmetry. Single left submandibular lymph node was palpable measuring approximately 1 cm × 1 cm in size, roughly spherical in shape, freely mobile, firm in consistency, and non tender on palpation. Intra orally she had complete denture in the maxillary arch and fixed partial dentures in the lower arch and missing teeth in relation to 38.

Local examination revealed a solitary, sessile, well-defined exophytic soft-tissue growth on left retromolar region behind 37, measuring about 2 cm × 3 cm, oval in shape, smooth surface, firm in consistency, involving the buccal, and the lingual alveolar ridge. Mucosa over the swelling looked stretched with no change in color, and was associated with tenderness. Teeth crustations seen on the lingual aspect of the lesion [Figure 1]. Based on the clinical features and the history provisional diagnosis of Irritational Fibroma of the left retromolar region was given. First differential diagnosis of minor salivary gland tumor was ruled out because of the history of continuous irritation from the upper denture. Based on the consistency, size and location of the lesion retention phenomenon – mucocele and lipoma could be ruled out, as they are soft in consistency, usually smaller in size and commonly seen in buccal mucosa, lip, etc. Squamous cell carcinoma could be considered as a last differential diagnosis because of the presence of chronic irritation, moreover because of the absence of surface ulceration.
Figure 1: Exophytic soft tissue growth on left retromolar region

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Patient was advised panoramic radiograph and cone-beam computed tomography (CBCT). Orthopantomogram revealed mild osteolytic changes in the region of 38. The cortical border (external oblique ridge) is continuous, but thinned out in comparison to the opposite side. Inferiorly the mylohyoid ridge is continuous, with large trabecular spaces anterior to the lesion [Figure 2]. CBCT was performed which revealed, superficial notching (scooping) of the bone towards the lingual aspect in the region of 38 in the coronal and sagittal section. The lesion is about 2mm superior to the inferior alveolar nerve canal [Figure 3]b and [Figure 3]c. In the axial section there is loss of bony trabeculae with continuous buccal and lingual cortical plates and inferior alveolar nerve is in the center [Figure 3]d, [Figure 3]e and [Figure 3]f. 3D section reveals superficial scooping of the bone [Figure 3]a. Radiographic diagnosis of benign tumor of the jaw was given.
Figure 2: Orthopantomogram showing mild osteolytic changes in the region of 38

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Figure 3: Cone-beam computed tomography (CBCT) images shows (a) superficial notching of the bone in the region of 38. (b and c) Coronal and sagittal sections of CBCT reveals, superficial notching (scooping) of the bone towards the lingual aspect in the region of 38. The lesion is about 2 mm superior to the inferior alveolar nerve (IAN) canal. (d-f) Axial sections at various levels of the lesion shows loss of bony trabeculae with continuous buccal and lingual cortical plates and inferior alveolar nerve (IAN) is in the center. (d) At surface of the lesion; (e) at the base of the lesion; (f) 1mm above the IAN canal

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The osteolytic changes noticed here are infiltrative in nature and not just pressure changes as the lesion was not big enough to cause resorption of bone due to pressure.

Incisional biopsy was carried out and sent for histopathological examination, which showed islands of tumor cells proliferating within the stromal tissue. Numerous intermediate cells along with squamous cells were seen proliferating within islands. Few vacuolated cells were also evident. There was minimal cellular atypia. The tumor cells are well separated from the overlying epithelial tissue by loose fibrous connective tissue [Figure 4]. The final diagnosis of “ MEC” of intermediate grade was given.
Figure 4: Hematoxylin and eosin (H and E) section of Mucoepidermoid carcinoma

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The patient was referred to oral and maxillofacial surgery for radical surgical excision of the lesion. The post-treatment patient is recalled for periodic check-up.

   Discussion Top

The embryological, histological, and anatomic characteristics of the oral cavity associated with environmental factors provide plenty of opportunities for the growth of asymptomatic or symptomatic lesions.[5]

Salivary gland tumors account for 5% of all the head and neck neoplasms. Tumors of the minor salivary glands account for 10–15% of all salivary gland neoplasms. Chief complaint is mostly a painless swelling in the mouth (60%). The most common sites for tumors of minor salivary gland origin are the palate (55%), buccal mucosa, and upper lip,[6] whereas in the retromolar region it is quite rare. There have been reports of primary cutaneous MECs originating in sweat glands and also in the vermillion border of the lower lip, where there are no salivary glands. MEC is believed to be more prevalent in women about 60.2%.[4] We present case of intraoral MEC in a middle aged female patient.

MEC was first described by Volkmann in 1895, and later was again described by Masson and Berger in 1924,[7] further elaborated upon by Stewart in 1945 as mucoepidermoid tumor. MEC may arise from pluri potent reserve cells of the excretory ducts of salivary gland which have the potential to differentiate into squamous, columnar, and mucous cells.[1],[4]

The clinical presentation of MEC of the minor salivary gland present as a bluish or red purple, fluctuant, smooth surfaced mass that is often clinically mistaken as mucocele. The palate is the most common site for minor salivary gland involvement, which accounts for 55%.[6],[7] In our present case, retromolar region is involved which is a very rare location. Usually, MEC is an asymptomatic swelling, a mass(growth) may cause some degree of discomfort. Other symptoms include pain, trouble with dental prosthesis retention, etc. In some cases the tumor may be incidentally discovered by a dentist.[7] Present case also showed similar symptoms. Among major salivary glands, MEC most frequently arise in the parotid gland, and presents as a painless swelling, with or without facial nerve involvement.[7]

Histologically, the MEC is characterized by the presence of mucous, squamous, and intermediate cells (with epidermoid metaplasia). The pattern is cystic or cystic papillary.[8],[9] They may be classified into low, intermediate, or high malignancy grade based on five parameters: proportion of cystic and solid elements, neural invasion presence, necrosis, anaplasia, and mitotic rate.[9] High-grade MEC is highly aggressive tumor, whereas low-grade shows more benign nature even though metastases have also been described in low-grade MEC. Mode of metastasis may be lymphatic (cervical lymph node) and hematogenous. Most common site for the metastasis is the lungs, bones are rarely involved.[7] Our case was of intermediate grade.

MEC, have a prognosis based upon the clinical stage and histological grade with a good prognosis of MEC in children as majority of them are well-differentiated or grade I neoplasm. Low-grade MEC has a better 5-year survival rate from 92% to 100% compared to high-grade MEC with 0–43% survival rate with an overall incidence of lymph node involvement ranges from 18% to 28%.[7],[10] Surgery is the main mode of treatment and different types of surgical interventions depends on the extent of the primary tumor.[7] Radical surgical excision of the lesion was done in our case.

Isolated tumors, as seen in our case, in the retromolar trigone are rare because of its small space. The stage of the lesion upon diagnosis is important because more advanced cases require more complex treatments, and the prognosis is poor.[10],[11] In most oral tumor cases, the diagnosis is late since patients look for experts only when the lesions are very advanced or inoperable. This is unacceptable since the oral cavity is easy to access and inspect, so late diagnoses are not justified.[4]

Dentist sensitization and training regarding the thorough examination of the stomatognathic system is critical to promote early diagnosis and prevent oral lesions, consequently requiring less invasive surgeries that result in better quality of life for the patient.[4]

   Conclusion Top

Many a times, atypical locations and innocent appearing tumor such as the one reported can mislead the practitioner resulting in incorrect diagnosis. The present case enlightens us about the importance of newer modalities of investigations like CBCT and biopsy as the gold standard in the confirmation of diagnosis. MEC should be considered as a diagnostic hypothesis in all oral proliferative lesions, even if its clinical appearance does not suggest malignancy.

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.

   References Top

Phasha Z, Sharma K. Mucoepidermoid carcinoma of palate mimicking vascular lesion: A case report. J Dent Sci Res 2013;4:9-12.  Back to cited text no. 1
Kolude B, Lawoyin JO, Akang EE. Mucoepidermoid carcinoma of the oral cavity. J Natl Med Assoc 2001;93:178-84.  Back to cited text no. 2
Triantafillidou1 K, Dimitrakopoulos J, Iordanidis F, Koufogiannis D. Mucoepidermoid carcinoma of minor salivary glands: A clinical study of 16 cases and review of the literature. Oral Dis 2006;12:364-70.  Back to cited text no. 3
Bharathi U, Mahesh MS, Lingaraju N, Basappa S, Kalappa TM. Mucoepidermoid carcinoma of palate: A case report. IJSS Case Rep Rev 2014;1:3-5.  Back to cited text no. 4
Ito FA, Ito K, Vargas PA, de Almeida OP, Lopes MA. Salivary gland tumors in a Brazilian population: A retrospective study of 496 cases. J Oral Maxillofac Surg 2005;34:533-6.  Back to cited text no. 5
Jansisyanamont P, Blanchaert RH Jr, Ord RA. Intraoral minor salivary gland neoplasms: A single institution experience of 80 cases. Int J Oral Maxillofac Surg 2002;31:257-61.  Back to cited text no. 6
Maloth A, Nandan SR, Kulkarni PG, Dorankula SP, Muddana K. Mucoepidermoid carcinoma of floor of the mouth – ararity.J Clin Diagn Res 2015;9:ZD03-4.  Back to cited text no. 7
Salazar C, Marcos J, De Saa MR, Sánchez-Jara JL, García M, González MA. Carcinoma mucoepidermóide de vestíbulo nasal. Acta Otorrinolaring Esp 2000;51:729-32.  Back to cited text no. 8
Thomas GR, Regalado JJ, McClinton M. A rare case of mucoepidermoid carcinoma of the nasal cavity. Ear Nose Throat J 2002;81:519-22.  Back to cited text no. 9
Rapidis AD, Givalos N, Gakiopoulou H, Stavrianos SD, Faratzis G, Lagogiannis GA,et al. Mucoepidermoid carcinoma of the salivary glands. Review of the literature and clinicopathological analysis of 18 patients. Oral Oncol 2007;43:130-6.  Back to cited text no. 10
Martins MAT, Marques FGOA, Pavesi VCS, Ramão MMA, Lascala CA, Martins MD. Avaliação do conhecimento sobre o câncer bucal entre universitários. Rev Bras Cir Cabeça Pescoço 2008;37:191-7.  Back to cited text no. 11


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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