|Year : 2015 | Volume
| Issue : 2 | Page : 278-281
Proliferative ameloblastomatous calcifying cystic odontogenic tumor of the mandible: A rare histological variant
Kamala Rawson, Basavaraj N Kallalli, Nimesh Patel, Yatriben Sandesara
Department of Oral Medicine and Radiology, Narsinhbhai Patel Dental College and Hospital, Visnagar, Gujarat, India
|Date of Submission||10-Jan-2015|
|Date of Acceptance||11-Oct-2015|
|Date of Web Publication||21-Nov-2015|
Department of Oral Medicine and Radiology, Narsinhbhai Patel Dental College and Hospital, Visnagar, Gujarat
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Calcifying cystic odontogenic tumor (CCOT) is an extremely rare clinical entity. It was considered as a cyst until 2005, when World Health Organization included it among the odontogenic tumors. It presents as a slow-growing, painless swelling of the jaw. Radiographically, it may be seen as a unilocular or multilocular radiolucency. Here, we present a case of a proliferative ameloblastomatous type of CCOT of the left mandible. Conventional radiography and cone beam computed tomography were performed, in which the lesion was found to be unicystic without any sign of calcification. The lesion was also associated with an impacted 37 tooth, which was displaced to the inferior border of the mandible.
Keywords: Ameloblastic proliferation, CCOT of mandible, cone beam computed tomography, ghost cell, Gorlin cyst
|How to cite this article:|
Rawson K, Kallalli BN, Patel N, Sandesara Y. Proliferative ameloblastomatous calcifying cystic odontogenic tumor of the mandible: A rare histological variant. J Indian Acad Oral Med Radiol 2015;27:278-81
|How to cite this URL:|
Rawson K, Kallalli BN, Patel N, Sandesara Y. Proliferative ameloblastomatous calcifying cystic odontogenic tumor of the mandible: A rare histological variant. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2019 Sep 17];27:278-81. Available from: http://www.jiaomr.in/text.asp?2015/27/2/278/170157
| Introduction|| |
Calcifying cystic odontogenic tumor (CCOT) is a ghost cell tumor, which was first described by Gorlin et al. in 1962.  World Health Organization (WHO) has classified calcifying odontogenic cyst as an odontogenic tumor in 2005.  Calcifying cystic odontogenic tumor may be associated with other odontogenic tumors. , Ameloblastomatous CCOT may be the most important of all other coexisting odontogenic tumors.  Calcifying cystic odontogenic tumor is a rare odontogenic tumor.  Praetorius et al. proposed that calcifying odontogenic cyst (COC) comprises of two entities: A cyst and a neoplasm. The ameloblastomatous proliferative COC is classified as type III in cystic variety. , The characteristic histopathologic feature is the presence of variable amounts of aberrant epithelial cells without nuclei called as ghost cells, which may become calcified.  Radiographically, it presents both completely radiolucent and/or radiolucency with diffuse radiopacities. The lesion appears usually unilocular and rarely multilocular. , Treatment is usually conservative by surgical enucleation with long term follow-up.  Here, we are presenting a case report of proliferating ameloblastomatous type of calcifying cystic odontogenic tumor of the mandible.
| Case Report|| |
A 15-year-old female patient visited the department of Oral Medicine and Radiology with the complaint of a swelling on the left side of the mandible since 6 months. Extra-oral examination revealed a solitary swelling involving one-third of the lower jaw on the left side. On palpation, the swelling was bony hard in the center and soft at the periphery. The skin over the swelling was normal [Figure 1]. Intra-oral hard tissue examination revealed presence of 11-17, 21-27, 31-36, 41-47, and missing 37 and none of the teeth were mobile. 36 was slightly tilted lingually. On soft tissue examination, slight obliteration of the buccal vestibular sulcus was noted [Figure 2]. On vitality test, 36 was non vital. Aspiration revealed a straw-colored fluid [Figure 3]. Based on the history, clinical findings, and chair side investigation, a provisional diagnosis of dentigerous cyst in relation to 37 was made. The differential diagnosis included were unicystic ameloblastoma, keratocystic odontogenic tumor, and CCOT.
|Figure 1: Profile picture of the patient showing facial asymmetry on the left side|
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|Figure 2: Intraoral photograph of the patient showing obliteration of the buccal vestibule in 37 and 38 teeth region|
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|Figure 3: The photograph of the aspiration showing a yellow-colored fluid|
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Hematological investigations followed by radiographic investigations were performed. Blood investigations were within the normal limits. Panoramic radiography revealed a unilocular radiolucency involving the left angle and entire ramus of the mandible. The radiolucency was well-defined, surrounded by a sclerotic border which was scalloped and thinning of the lower border of mandible with displacement of 37 was noted [Figure 4]. Cone beam computed tomography (CBCT) revealed a well-demarcated unilocular radiolucent lesion associated with impacted 37 tooth within the lesion, with a thinning of the cortex. Lateral aspect of 3D-CBCT showed destruction of the anterior surface of the ramus [Figure 5]a and b.
|Figure 4: Panoramic radiograph showing a unilocular radiolucency in the left body and ramus of the mandible associated with an impacted 37 tooth|
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|Figure 5: Sagittal CBCT revealed a well-demarcated unilocular radiolucent lesion associated with impacted 37 tooth, showing thinned out cortex (a) CBCT with panoramic reconstruction revealing an extensive radiolucency associated with impacted 37 (b) 3D-CBCT showing destruction of the anterior surface of the ramus|
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Treatment of the lesion was performed under general anesthesia, which included enucleation of the cystic lesion with extraction of 37 [Figure 6]. Histopathological examination revealed the cystic lining to be stratified epithelium with cuboidal to columnar basal cells, few showing reverse polarity of the nucleus. Suprabasal cells were stellate reticulum like and few areas showed ghost cells. Juxta-epithelial dentinoid-like material were seen [Figure 7]. The stroma showed thick collagen with hyalinization in few areas. Odontogenic follicles were seen with cystic degeneration [Figure 7]a. Proliferating cystic lining and epithelial budding within the capsule were seen [Figure 7]b. Histopathologic features were suggestive of ameloblastoma proliferating type of CCOT.
|Figure 7: 10× H&E stained section showing cuboidal basal cells, stellate reticulum-like cells, ghost cells in epithelium and dentinoid like material at juxta-epithelial junction. (a) 10×- H&E section showing odontogenic island (b) 4×- H&E section showing cystic lining with epithelial budding|
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| Discussion|| |
The CCOT is believed to have an odontogenic origin, which is from the odontogenic epithelial remnants. The tumor can arise in the soft tissue (peripheral variety) or inside the bone (central variety).  Calcifying cystic odontogenic tumor may occur as a solitary tumor or in association with other odontogenic tumors, odontoma being the most common (24%).  There are various lesions showing histopathological features simikar to CCOT, like orthokeratinized odontogenic cyst (OOC), ameloblastoma, ameloblasticfibroodontoma, odontogenic myxofibroma, ameloblastic fibroma, and adenomatoid odontogenic tumor with fibro-odontoma. 
Most of the classifications of CCOT have included the ameloblastoma associated variety of CCOT (ameloblastomatous CCOT). A classification by Hong et al. has two varieties of COC associated with ameloblastoma; ameloblastomatous cystic and neoplastic type associated with ameloblastoma.  The cystic variety is unicystic with lining epithelium showing unifocal or multifocal intraluminal proliferative activity resembling an ameloblastoma, but also containing ghost cells and calcification either isolated or in clusters. 
Because of the rarity of ameloblastomatous CCOT, determination of the most common age, sex and location of this lesion is difficult. According to literature, it is most commonly seen between the age group of 10-30-years old, and the tumor tends to involve the posterior region of the mandible.  These findings were similar to the present case. As far as the sex of the patients is concerned, no predilection has been observed.  Clinically, CCOT appears as a slow growing and painless swelling of the jaw.  Pain is an occasional symptom. The expansion of the jaw may destroy the cortical plate. Aspiration of the tumor yields yellow-colored, viscous, granular fluid in most cases. 
Radiographically, CCOT mostly (75%) occurs in the bone as an intra-osseous variety manifesting usually as a pericoronal radiolucency. It appears as a well-defined cystic lesion associated with an impacted tooth (20-50% cases), with variable internal structure ranging from completely radiolucent in some cases to small foci of calcified materials as flecks or pebbles, or larger, solid, and amorphous masses. The lesion may also appear multilocular rarely. The tumor may also cause tooth displacement, root resorption, and the cortical plate may also get perforated.  Cone beam computed tomography has shown its effectiveness in assessment of the internal calcification, extent, and the complex relationship of CCOT with tooth, jaw, and other lesions (odontogenic tumor). 
The differential diagnosis of ameloblastomatous CCOT includes dentigerous cyst, ameloblastic fibro-odontome and CEOT.  Histopathologically, the presence of variable numbers of altered epithelial cells without nuclei, also called as "ghost cells," with a propensity to calcify is the characteristic feature of CCOT.  In the ameloblastomatous type, ghost cells are seen in ameloblastomatous epithelial islands.  The recurrence is very uncommon after a complete excision. So, CCOT is treated conservatively by surgical enucleation under general anaesthesia with a long term follow up,  whereas, the ameloblastomatous CCOT should be treated similar to an ameloblastoma. The complication of untreated cases includes expansion of the lesion with rare recurrence. 
| Conclusion|| |
Calcifying cystic odontogenic tumor is an extremely rare entity, with the ameloblastomatous proliferating type being even rarer. So far very few cases have been reported in literature. In the present case, the clinical and radiographic findings were suggestive of dentigerous cyst. Histopathological examination remains the gold standard for the definitive diagnosis. Cone beam computed tomography was much more accurate in assessing the exact extent of the lesion, margins, relationship with adjacent structures which helped in better treatment planning and prognosis. Long-term follow-up visits are recommended, especially if adjacent structures are also affected.
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.
We would like to thank Dr. Priya Sahni, Professor and Head of Department of Oral and Maxillofacial Pathology, NPDCH for the valuable help in slide preparation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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