|Year : 2014 | Volume
| Issue : 2 | Page : 57-60
Calcifying epithelial odontogenic cyst of the mandible
Nigel R Figueiredo1, Manoj Meena2, Ajit D Dinkar1, Manisha Khorate1
1 Department of Oral Medicine and Radiology, Goa Dental College and Hospital, Bambolim, Goa, India
2 Department of Oral Medicine and Radiology, Rajasthan Dental College, Jaipur, Rajasthan, India
|Date of Web Publication||10-Mar-2015|
Nigel R Figueiredo
House No. 685, Santerxette, Aldona, Bardez, Goa
Source of Support: None, Conflict of Interest: None
The calcifying epithelial odontogenic cyst (CEOC) is a developmental odontogenic cyst, which was first categorized as a distinct entity by Gorlin in 1962. It is an unusual and unique lesion, which may show characteristics of both a solid neoplasm and a cyst. It usually occurs as an intra-osseous lesion but may occasionally occur as an extra-osseous or peripheral variant. It shows a nearly equal distribution between the maxilla and mandible and is commonly seen anterior to the first molar. The clinical and radiographic features of this lesion are not pathognomonic, and it is characterized by its histological diversity, with the most characteristic feature being the presence of a variable number of ghost cells within the epithelial component. Treatment is conservative with surgical enucleation, and recurrences are rare. This report describes a case of CEOC in association with an impacted mandibular first premolar, which was diagnosed in a 13-year-old female patient, along with a review of the literature.
Keywords: Calcifying odontogenic cyst, ghost cells, unilocular
|How to cite this article:|
Figueiredo NR, Meena M, Dinkar AD, Khorate M. Calcifying epithelial odontogenic cyst of the mandible. J Oral Res Rev 2014;6:57-60
|How to cite this URL:|
Figueiredo NR, Meena M, Dinkar AD, Khorate M. Calcifying epithelial odontogenic cyst of the mandible. J Oral Res Rev [serial online] 2014 [cited 2019 Mar 25];6:57-60. Available from: http://www.jorr.org/text.asp?2014/6/2/57/152909
| Introduction|| |
Calcifying epithelial odontogenic cyst (CEOC) (also called as Gorlin's cyst or calcifying odontogenic cyst) is an uncommon benign odontogenic lesion that was first categorized as a distinct entity by Gorlin in 1962. It is an unusual and unique lesion which occupies a spectrum ranging from a cyst to an odontogenic tumor, with characteristics of a cyst alone or sometimes those of a solid neoplasm (epithelial proliferation and a tendency to continue growing). 
In 1992, the WHO classified the CEOC within the groups of neoplasms and tumors that originate from odontogenic tissues, but confirmed that most of the cases are nonneoplastic.  In view of this duality, many different terminologies (like dentinogenic ghost cell tumor, calcifying cystic odontogenic tumor and atypical adamantinoma) have been applied to the cystic and solid CEOC variants, but CEOC is still the preferred term. [3,4]
Calcifying epithelial odontogenic cyst most often occurs as a central (intra-osseous) lesion, whereas peripheral (extra-osseous) localization in the soft tissue is rare. It normally appears as a painless, slow-growing tumor, and shows a nearly equal distribution between the maxilla and mandible, with a predilection for the anterior region (incisor/canine area).  The definitive diagnosis is made histologically, due to the lesion's lack of characteristic clinical and radiological features, as well as its variable biological behavior. [6,7]
This paper reports a case of CEOC in association with an impacted right mandibular first premolar in a 13-year-old female patient, which clinically and radiographically mimicked a dentigerous cyst.
| Case Report|| |
A 13-year-old female patient reported to our out-patient department with a chief complaint of swelling over the right side of the face since 4 months. History revealed that the swelling was initially small in size and had progressively increased to its present size. On extra-oral examination, no facial asymmetry was evident. However, a diffuse hard swelling over the right body of mandible was evident on palpation.
Intra-oral examination revealed a diffuse swelling in the 43 and 44 region, extending from 42 on the buccal aspect till the 45 region, causing obliteration of the buccal vestibule [Figure 1]. The swelling was firm in consistency with a smooth surface and nontender on palpation. Examination of the teeth showed that 44 was clinically missing. No tenderness or mobility of the adjacent teeth was noted.
|Figure 1: Intra-oral view showing a diffuse swelling in the 43 and 44 region with obliteration of the buccal vestibule|
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An intra-oral periapical radiograph showed a unilocular radiolucency with a well-defined thin corticated border associated with an impacted 44, encircling the pericoronal region of 44, and extending up to the distal aspect of the root of 43. The internal structure appeared radiolucent. The root of 45 showed divergence distally and was in close proximity to the mesial root of 46 [Figure 2].
|Figure 2: Intra-oral periapical radiograph showing a unilocular radiolucency with a thin corticated border in association with an impacted 44|
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A mandibular true occlusal view showed expansion of the buccal cortical plate in relation to 43 and 44, with the presence of a thin but intact cortical boundary [Figure 3]. An orthopantomograph showed a unilocular radiolucency with a well-defined thin corticated border associated with an impacted 44, encircling the pericoronal aspect of 44. The lesion was attached to the cervical area of 44 on the distal aspect, and to the middle one-third of the root of 44 on the mesial aspect. The internal structure appeared radiolucent. Divergence of the root of 43 in a mesial direction and 45 distally was evident [Figure 4].
|Figure 3: Mandibular true occlusal radiograph showing expansion of buccal cortical plate in the region of 43 and 44|
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|Figure 4: Orthopantomograph showing a unilocular radiolucency with a well-defined thin corticated border and radiolucent internal structure associated with an impacted 44, encircling the pericoronal region of 44|
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Based on the history, clinical and radiographic findings, a provisional diagnosis of a dentigerous cyst was made. A radiographic differential diagnosis of CEOC, adenomatoid odontogenic tumor, and calcifying epithelial odontogenic tumor was considered. The lesion was treated conservatively with careful enucleation and curettage. Histopathological examination showed a cystic lesion with a fibrous capsule lined by epithelium with a cuboidal or columnar palisaded basal layer of cells with hyperchromatic nuclei. The upper epithelial layer was similar to stellate reticulum. Numerous pale, eosinophilic ghost cells with granular eosinophilic cytoplasm and faint nuclear outline were seen in the connective tissue [Figure 5] and [Figure 6]. Some of the ghost cells showed dystrophic calcifications. Irregular foci of tissue resembling dentin, which were atubular, were observed in the connective tissue. Thus, based on the histopathology of the enucleated tissue, a final diagnosis of a CEOC was made.
|Figure 5: Histopathology (H and E) showing a cystic lesion lined by epithelium with cuboidal or columnar palisaded basal layer of cells and numerous pale, eosinophilic ghost cells with granular eosinophilic cytoplasm in the connective tissue|
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|Figure 6: High-power view (×40) (H and E) of ghost cells with granular eosinophilic cytoplasm and faint nuclear outline|
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Postoperative healing was uneventful. The patient was under regular follow-up for 1 year, during which time clinical and radiographic examination revealed no evidence of recurrence. The patient was scheduled to undergo orthodontic treatment for the impacted tooth, but did not report back.
| Discussion|| |
The CEOC is usually a nonaggressive cystic lesion lined by odontogenic epithelium that resembles that of the ameloblastoma, but with characteristic ghost cell keratinization. It is a developmental odontogenic cyst, and its occurrence constitutes about 0.3-0.8% of all odontogenic cysts. 
Calcifying epithelial odontogenic cyst's are thought to be a unicystic process, which develop from the reduced enamel epithelium or remnants of odontogenic epithelium in the follicle, gingival tissue or bone.  The epithelial lining of a CEOC appears to have the ability to induce the formation of dental tissues in the adjacent connective tissue wall, and may thus be associated with other odontogenic tumors. 
The age of these patients may range from 5 to 92 years, with a peak incidence in the second decade of life.  Other authors however state a bimodal age distribution, with a second peak in the sixth-seventh decade of life. [1,3] The lesion has no sex predilection and is equally distributed between the maxilla and mandible.
Calcifying epithelial odontogenic cyst commonly occurs anterior to the first molar region in which 75% of cases are in the incisor-canine region or inter-canine region, usually crossing the midline in the mandible, which is however a rare feature in the maxilla. Clinically, the lesion usually presents as an asymptomatic swelling causing a hard bony expansion of the jaw.  Early lesions are usually detected following routine radiographic examination, and they are often associated with an unerupted tooth. The peripheral variant occurs on the gingiva as a nonspecific well-circumscribed sessile or pedunculated mass with a smooth surface, which may resemble a gingival fibroma gingival cyst or peripheral giant cell granuloma.  The present case was diagnosed in a 13-year-old female, who presented with an asymptomatic bony swelling in relation to the right mandibular first premolar, which was clinically missing.
Radiographically, majority of the lesions present in an unilocular form with well-defined corticated margins during 5-13% of cases are multilocular.  The internal structure may vary in appearance - it may be completely radiolucent, but is usually mixed (radiolucent-radiopaque), and may have scattered irregular sized calcifications producing a variable range of opacities (salt and pepper type of pattern), or may even show large solid amorphous masses.  Central CEOC has been reported to be associated with an odontoma in 24-35% of cases and with impacted teeth in 35% cases, usually a canine.  Unilocular lesions may mimic dentigerous, radicular or residual cysts while multilocular lesions may resemble ameloblastomas or odontogenic keratocysts.  Our case appeared as a unilocular radiolucency with a radiolucent internal structure surrounding the crown of an impacted mandibular first premolar and thus showed findings similar to those reported in the literature. Expansion of the buccal cortical plate was seen, and the lesion resembled a dentigerous cyst radiographically.
Over the years, various authors have attempted to classify and group this lesion owing to its unique character. Praetorius (1981) proposed a classification for grouping CEOC as Type I (cystic type) and Type II (neoplastic type [dentinogenic ghost cell tumor]). He further sub-divided the cystic variant (Type I) into three different types:
(a) Simple unicystic type,
(b) Odontome-producing type, and
(c) Ameloblastomatous proliferating type. [8,10]
Toida (1998) proposed a classification, in which he called the cystic variant as calcifying ghost cell odontogenic cyst (CGCOC) and used the term calcifying ghost cell odontogenic tumor (CGCOT) for the neoplastic variant, as given below: [4,10]
1. Cyst: CGCOC
A. Benign - CGCOT
B. Malignant - Malignant CGCOT
- Cystic variant - Cystic CGCOT
- Solid variant - Solid CGCOT
3. Combined lesion: Each of the categories above associated with the following lesions:
The histological features of a classical CEOC include a cystic cavity with a fibrous capsule, with a lining of odontogenic epithelium that is 6-8 cells thick. The basal layer is made up of ameloblast-like columnar or cuboidal cells with hyperchromatic nuclei polarized away from the basement membrane. The overlying loosely arranged epithelial layer shows similarity to the stellate reticulum of the enamel organ.  The typical microscopic characteristic of this lesion is the presence of variable amounts of aberrant epithelial cells, devoid of nuclei, which are eosinophilic and retain their basic cell outline, and are called "ghost cells."  These ghost cells may undergo calcification and lose their cellular outline to form sheet-like areas of calcified keratin. The nature of ghost cell change is controversial - it may be due to the effect of coagulative necrosis and dystrophic calcification or may be a form of normal or abnormal keratinization of the odontogenic epithelium. Ghost cells are not unique to CEOC, but are also seen in odontoma, ameloblastoma, craniopharyngioma, and other odontogenic tumors.  The present case showed all the typical features of CEOC, with the presence of a cystic epithelial lining with ameloblast-like cells, ghost cells, dystrophic calcification and irregular areas of dysplastic dentin.
- Other odontogenic lesions.
The CEOC is treated conservatively by surgical enucleation and recurrences are very uncommon (recurrence depends on the completeness of cyst removal). The malignant transformation of a preexisting benign CEOC can occur but is extremely uncommon.  The CEOC may also be associated with other odontogenic tumors such as adenomatoid odontogenic tumor, ameloblastoma, ameloblastic fibro-odontoma and ameloblastic fibroma, where wider excision may be required. 
| Conclusion|| |
The CEOC is an uncommon lesion which may show characteristics of both a cyst and a solid neoplasm. Its clinical and radiographic features may mimic other odontogenic cysts/tumors, and a definitive diagnosis can only be made histologically. The present case showed nonspecific clinico-radiographic findings, which resembled a dentigerous cyst. Our case can be classified as a Type I(a) (simple unicystic type) of calcifying odontogenic cyst (according to the classification proposed by Praetorius).
| Acknowledgments|| |
Dr. Anita Spadigam, Professor and Head, and Dr. Anita Dhupar, Assistant Professor, Department of Oral and Maxillofacial Pathology, Goa Dental College and Hospital, Bambolim, Goa, India, for the histopathological analysis and photographs.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]