CALCIFYING EPITHELIAL ODONTOGENIC TUMOR OF POSTERIOR MAXILLA: A RARE CASE REPORT

Calcifying epithelial odontogenic tumor (CEOT), also known as Pindborg tumor, is a rare benign but locally aggressive odontogenic neoplasm, accounts for<1% of all odontogenic tumors.The tumor has a recurrence rate of 10%–20% and so periodic follow-up is necessary. Here is reported the case of a 21-year-old female patient with a CEOT in the right maxillary region of the jaw. confirmed diagnosis. Early surgical intervention is advocated for the treatment of histopathologically confirmed calcifying epithelial odontogenic tumors as the recurrence rate reported are around 10-20 % to prevent the tumour expanding beyond confines of maxilla or mandible.


ISSN: 2320-5407
Int. J. Adv. Res. 10(03), 65-70 66 and not cause much disfigurement of the face, the patient did not consult to the clinician. With due time swelling size increased and associated with intermittent pain. Her past medical and family history was non-contributory. On examination her face was asymmetrical, with slight extraoral swelling was seen.
Intraorally a well-defined expansile swelling seen in the maxillary posterior region extended from 15-to 16 region, lesion entirely positioned buccal to first molar which was firm, tender on palpation and bony hard in consistency. Figure 1: (a) lesion on right posterior region of maxilla.
Overlying skin appeared normal and on palpation the swelling was bony hard and there was mild tenderness present. There was no involvement of the lymph nodes. Intraoral examination revealed root stumps of 16,14,13,12,11 and decayed 27.
A panoramic radiograph showed a well-defined unilocular radiolucency with a corticated margin extending from the root of tooth 15 to the root of 13 area, which measured about 2cm x 1.5cm in diameter. Figure 1: (b) lesion on radiograph involving right first molar with root stump of the tooth.
Gross examination of the surgical specimen included small bit of soft tissue measuring approx. 0.8x0.7x0.5cm in total. Specimen was brownish in color and soft to firm in consistency.
Microscopic features revealed the presence of non-keratinized stratified squamous epithelium showing arcading pattern with moderately collagenous connective tissue stroma. Epithelial islands show dystrophic calcification within the amyloid like material forming concentric rings (Liesegang rings). Numerous blood vessels lined by endothelial cells and few areas of focus show multinucleated giant cells and clear cells.

Special stain:
The amyloid like material was positive for Congo Red special stain.

Discussion:-
The calcifying epithelial odontogenic tumor is classified as an uncommon, benign, odontogenic neoplasm that exclusively epithelial in origin, the etiology of which remain enigmatic. The source of epithelial cells initially suggested by Pindborg was reduced enamel epithelium but today, most investigators believe the cells of origin are stratum intermedium 1 .
There have been very few reported cases in the maxilla till date and posterior maxilla being the rarest site. This case adds to a small number of Pindborg tumor cases located in the maxilla. Three distinctive features of the present case are: a rare localization of the lesion, presentation as an ulcerated mass, and a comparatively young age of patient.
According to Pindborg, the characteristic histologic criteria for diagnosis of CEOT are sheets of large polygonal epithelial cells that have well-defined borders and show prominent intercellular bridges. Nuclear pleomorphism varied with size, shape, and number. Cellular abnormalities and mitotic figures are rarely seen. Cytoplasm is abundant and eosinophilic. Varying amounts of extracellular amyloid-like material that stains Congo red positive in polarized light 8,9 . This amyoid like material has been extensively investigated by histochemical, immunohistochemical, ad biochemical methods. It has been identified as unique protein that is produced by this tumor, as well as by the normal odontogenic apparatus and other odontogenic neoplasms and this material has been designated as "odontogenic ameloblast associated protein" (ODAM) 10 . The presence of calcifications in CEOT may have prognostic implications. The absence of calcification indicates a poorly differentiated tumor with more chance of recurrence. The differential diagnosis of CEOT includes calcifying epithelial odontogenic cyst, adenomatoid odontogenic tumor, ameloblastoma, ameloblastic fibro-odontoma, odontogenic fibroma and ossifying fibroma [11][12][13] . To explain the pathogenesis Peacock et al conducted a study on seven cases of CEOT. They conclude that the sonic hedgehog pathway (SHH) to be involved in the development of CEOT and they also noticed mutation in PTCH1. PTCH1 is a tumor suppressor gene within the Sonic hedgehog pathway. The sonic hedgehog pathway regulates the development of multiple organ systems, including odontogenesis by controlling cell to cell interaction and cell proliferation in tissue. PTCH1 mutation first detected in nevoid basal cell carcinoma syndrome and has also been found in both CEOT and keratocystic odontogenic tumors. However, the clinical significance of these mutations is unknown. CEOT affected a wide range of ages, most commonly occurs between 20 and 60 years of age, with a peak incidence in the 5th decade and equal distribution between both gender. However, some cases reported before 20 years of age, present case also reported CEOT affected a 13-year-old female. It commonly presented as asymptomatic, slow-growing, and locally aggressive lesion. Initial clinical signs/symptoms of the lesion are a local expansion of bone with the migration of the teeth of the affected region. Later the overlying mucosa becomes so inflamed that even a slight trauma can lead to bleeding from that side. The premolar and molar region of the mandible is the most prevalent site for its occurrence. Although the case also reported in maxilla but less frequent as compared to mandible. The further central intraosseous form is the most common, larger, and more invasive and about 50% of cases show signs of cortical plate perforation. A study conducted by Bruno R. et al according to results the distribution of 247 cases of CEOT among different ethnic groups/races is as follows white-90, Asian-55, Indian -54, blacks -29, Hispanics-8, Persian/Iranian -6, and 5 in Turkish 1,13,14 .

Treatment
The treatment plan is dependent on multiple factors such as the size of the tumor, location of the tumor, general condition of patient and operator skill. Small, well-defined, intra-bony mandibular lesions can be treated by simple enucleation or curettage followed by judicious removal of a thin layer of bone next to the tumor. Larger tumors may need segmental resection, hemi-mandibulectomy and hemi-maxillectomy, followed by bone grafting or distraction osteogenesis 16 .
In our case, surgical excision along with the associated teeth was done.
The recurrence rate varies from 10% to 20% with the clear cell variant having a higher recurrence rate of around 15%. Malignant transformation is rare.
Thus, our report describes a case of CEOT with atypical clinical and radiographic features, which include occurrence in the posterior maxilla, root resorption of the teeth associated with the lesion and absence of calcifications radiographically.

Conclusion:-
CEOT also known as Pindborg tumor is typically a benign yet locally aggressive tumor more commonly seen in middle-aged adults, but can be seen in children, albeit rarely. Amyloid like matrix is a unique component that may be associated with tumor maturation and differentiation, and possibly lower risk of malignant transformation. Thorough clinical and radiological examination and careful histopathological interpretation are important for confirmed diagnosis. Early surgical intervention is advocated for the treatment of histopathologically confirmed calcifying epithelial odontogenic tumors as the recurrence rate reported are around 10-20 % to prevent the tumour expanding beyond confines of maxilla or mandible.