ABSTRACT : Mucoepidermoid carcinoma (MEC) is a malignant neoplasm of the

salivary glands. It majorly arises in the parotid gland followed by minor salivary glands but

rarely develops intraosseously. Primary intraosseous mucoepidermoid carcinoma of the

jaw bones is extremely rare. Literature search has revealed that very few cases have been

reported to date. Moreover, Primary intraosseous mucoepidermoidcarcinoma affects

females twice more frequently than males. The present report illustrates the clinical

,radiographic and histological features of a rare case of a primary central mucoepidermoid

carcinoma of the mandible in a 16 year old male patient. Central Salivary gland tumors

should be included in the differential diagnosis of unilocular and multilocular radiolucent

lesions of the jaws. Timely diagnosis and prompt management is important.

2 3 41Radhika Rai, Aparna Dave, Manpreet Arora, V.P.Shetty.1 2,3,4Assistant Professor, Professor, Department of Oral Pathology, Faculty of Dental Sciences, SGT University, Gurgaon

INTRODUCTION :

Salivary gland neoplasms constitute about 6 % of all head and

neck tumors1. Most salivary gland tumors arise in the parotid

gland while the remaining in submandibular, sublingual,

minor salivary glands and other rare sites1 . Besides the

occurrence of these tumors in the usual sites of major and

minor salivary glands, rarely they may also arise in ectopic

tissue sites. Ectopic salivary gland tissue has been found in the

jaws, lips, buccal mucosa, tongue ,skin, mastoid bone, middle

ear , nasopharynx, pharynx and trachea[2]. The primary

occurrence of salivary gland tumors at these unusual sites are

often a diagnostic challenge for the dental practioners.

Mucoepidermoid carcinoma comprises 5 –10% of all salivary

gland tumors and generally arises in the salivary glands.[3,4]

Stewart et al described its mucous secreting and epidermal

cellular elements thus establishing it as a distinct pathological

entity.[5] Mucoepidermoid carcinoma majorly involves the

parotid gland (89.6%), followed by sub mandibular(8.4 %)

and sublingual glands (0.4%) .6, 7The palate is the most

common site for minor salivary gland involvement,

accounting for 41.1% of intraoral lesions.[ 6,7]

Aberrant salivary gland neoplasms arising within the jaws as

primary central bony lesions are extremely rare comprising

2–3% of all mucoepidermoid carcinomas reported.[8] A

review of literature reveals that it generally occurs in the

fourth and fifth decades of life while only a few cases have

been reported in young patients[9]. The present report

illustrates one such rare case of a primary central

mucoepidermoid carcinoma of the mandible in a teenager.

CASE REPORT: A 16 year old male patient of Indian origin

reported with the complaint of pain and swelling on the left

side of his face for the last 2 months. The patient also had

difficulty in opening the mouth.

CENTRAL MUCOEPIDERMOID CARCINOMA OF MANDIBLE IN A TEENAGER: CASE REPORT AND REVIEW OF LITERATURE.

Dental Sciences

Key Words : primary intraosseousmucoepidermoid carcinoma; salivary gland ; mandible.

Source of support : NoneConflict of interest: Nil.

University Journal of Dental Sciences, An Official Publication of Aligarh Muslim University, Aligarh. India 76

University J Dent Scie 2016; No. 2, Vol. 2

CaseReport

Journal of University

Dental Sciences

The patient was apparently well 2 months back when he

observed a small swelling on the left side of his face. The

swelling slowly increased in size. Soon after, the patient also

experienced pain in the same area. The pain was gradual in

onset, mild in nature, continuous and radiating .He then

visited a local dentist for the same following which the

extraction of 37 was done. There was no relief. Instead the

swelling rapidly increased in size.

There was no significant past medical history, family history

or personal history. On general examination, the patient was

found to be moderately built and nourished and all vital signs

were within normal range.

Extraoral examination revealed a single diffuse swelling on

left side of face extending superior-inferiorly from outer

canthus of eye to inferior border of mandible and medio-

laterally from ala of nose to tragus of ear(Figure 1).

Figure . Profile photograph of patient

Left submandibular lymph nodes were palpable, tender, firm

and not freely movable. Intraoral examination revealed an ill

defined ulcer with rolled out everted margins extending from

mandibular left second premolar to retromolar region . There

was also reduced mouth opening (Figure 2).

Figure 2. Intra Oral photograph revealing swelling extending

from 35 to retromolar region with buccal cortical plate

expansion and reduced mouth opening.

Panoramic & PA view radiographs revealed a well defined,

multilocular radiolucency involving left posterior body, angle

and ramus region of mandible extending anteriorly from the

medial aspect of mandibular left second premolar to posterior

border of ramus and inferiorly from lower border of mandible

to superiorly involving coronoid and condylar process. The

cortex of inferior border of mandible at posterior body, angle

and ramus region was thinned out. Internal body septations

were present giving the radiolucency a multilocular

appearance with formation of spider web and various soap

bubble like compartments. The root apices of mesial and

distal roots of 36 showed resorption, 28 was pushed

superiorly at the condylar region with complete resorption of

coronoid process and condylar regions. (Figure 3 & 4)

Figure 3.Panoramic radiograph showing radiolucency from

medial aspect of 35 to posterior border of ramus, inferiorly

from lower border of mandible to superiorly involving

coronoid and condylar process.

Figure 4.Posterio Anterior view showing the thinning of

cortex of inferior border of mandible .

On microscopic examination, the H& E stained tissue section

showed islands of tumor cells invading connecting tissue

stroma. The cells seen were polygonal epidermoid like with

hyperchromatic nuclei. Areas of mucous cells with pale

foamy cytoplasm along with sheets of clear cells were also

evident. Mucin filled cystic spaces could also be appreciated.

The surrounding connective tissue exhibited collagen fibres,

blood vessels and extravasated RBCs. The features suggested

University Journal of Dental Sciences, An Official Publication of Aligarh Muslim University, Aligarh. India 77

University J Dent Scie 2016; No. 2, Vol. 2

of Mucoepidermoid Carcinoma. (Figure 5 &6)

Figure 5. Sheets of epidermoid and mucous cells ( H& E X40)

Figure 6. Areas showing clear cells along with Sheets of

epidermoid and mucous cells ( H& E X40)

DISCUSSION :

Primary central mucoepidermoid carcinoma is a rare lesion,

first described by Lepp in 1939[10] .

Central MEC affects females twice more frequently than

males and involves the mandible twice more often than the

maxilla with a predilection for the premolar-molar area[7,11].

It has been reported in all ages ranging from 1 to 78 years, with

the majority of cases occurring in the 4th and 5th decades of

life [12]. Its occurrence in children is rare.

Literature search has revealed that a very few cases have been

reported in puberty, suggesting a hormonal influence on

salivary glands[11]. The present case also reports the

occurrence of a Primary Central MEC in a 16 year old patient.

Clinically, the main symptoms are swelling and pain with

trismus, paresthesia and occasionally tooth mobility. [13,14]

Radiographic features are usually a well circumscribed

unilocular/multilocular radiolucency.

The chances of its central origin are more when the tumour is

in the mandible, since such lesions in maxilla may actually

arise from the submucosal mucous secreting glands in the

antrum, or represent intraosseous extension of minor salivary

gland tumours of the sinus mucosa. [15]

Regarding its pathogenesis four possible origins have been

described which include 1.)entrapment of retro molar mucous

glands within the mandible, which subsequently undergo

neoplastic transformation; 2).developmentally induced

embryonic remnants of the sub-maxillary gland within the

mandible;3). neoplastic transformation of the mucous

secreting cells commonly found in the pluripotent epithelial

lining of dentigerous cysts associated with impacted third

molars; and 4) neoplastic transformation and invasion from

the lining of the maxillary sinus.[16]

Several authors have suggested criteria required for diagnosing

a lesion as a central MEC, independent of whether it arises from

an odontogenic cyst or tumor. The most commonly accepted

criteria for diagnosis proposed by Alexander et al17.and

modified by Browand and Waldron[18 ] is:

1. Intact cortical plates (However, cortical perforation does

not exclude PIOC type 4)

2. Radiographic evidence of bony destruction

3. Exclusion of another primary tumour that in its

metastasis could histologically mimic the central tumour

4. Exclusion of an odontogenic tumour

5. Histopathological confirmation

6. Detectable intracellular mucin.

The case presented here had thinned out yet intact cortical

plates, evident bony destruction, the presence of any primary

tumor or odontogenic tumor was ruled out .The histological

picture confirmed the lesion and intracellular mucin was

detectable.

Brookstone and Huvos10, 13 suggested a three-grade

classification for intraosseous MEC Grade 1, without

expansion and rupture of cortical plate; grade 2, with

expansion but without rupture of cortical plate; grade 3, with

rupture of cortical plates or presence of regional metastasis.

Most central mucoepidermoid carcinomas have a good

prognosis, the preferred treatment of choice is wide surgical

excision with clear margins. Brookstone and Huvos13, 14

reported that among 64 patients with mandibular

mucoepidermoid carcinoma, [32] were treated conservatively

and 32 were treated radically. In the first group, there were 13

recurrences (40%) whereas there were only 4 recurrences

(13%) of the tumors treated radically. This suggests that

radical resection offers the best chance of tumor eradication

and prevention of local recurrence and late distant metastasis.

CONCLUSION :

Although central salivary gland tumors are relatively

uncommon but they should always be included in the

differential diagnosis of unilocular and multilocular

radiolucent lesions of the jaws. The clinical significance of

University Journal of Dental Sciences, An Official Publication of Aligarh Muslim University, Aligarh. India 78

University J Dent Scie 2016; No. 2, Vol. 2

malignant tumors arising from odontogenic cysts or de novo

should never be underestimated as illustrated by the present

case. A prompt biopsy must always be done for all

intraosseous, radiolucent lesions followed by a careful

histopathological evaluation of the excised tissue so that such

cases may be identified and treated effectively.

Radical surgery along with the adjuvant treatment must be

done. After the surgical procedure, post operative

radiotherapy and follow up examinations is advised to avoid

local recurrence and late distant metastasis. If identified,

treated and managed effectively, the overall prognosis of

Central MEC is good.

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CORRESPONDING AUTHOR:

Dr. Radhika Rai

House No. 174, Sector 11 –D, Faridabad, Haryana.

E mail : nagpal.j@gmail.com

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