|Year : 2015 | Volume
| Issue : 3 | Page : 649
Adenomatoid odontogenic tumor associated with a dentigerous cyst
BS Manjunatha1, Ashutosh Harsh2, Sharad Purohit3, Mahita V Naga1
1 Department of Oral Pathology and Microbiology, K M Shah Dental College and Hospital, Vadodara, Gujrat, India
2 Department of Dentistry, Dr. Sampurnanand Medical College and Hospital, Jodhpur, Rajasthan, India
3 Department of Oral Pathology and Microbiology, Jodhpur Dental College and Hospital, Jodhpur, Rajasthan, India
|Date of Web Publication||9-Oct-2015|
B S Manjunatha
Department of Oral Pathology and Microbiology, K M Shah Dental College and Hospital, Vadodara, Gujrat
Source of Support: None, Conflict of Interest: None
Adenomatoid odontogenic tumor (AOT) is a relatively uncommon benign lesion of odontogenic origin mainly affecting females in second decade of life, having a predilection for the anterior region of the maxilla. Histologically, it is composed of odontogenic epithelium in a variety of histopathological patterns in a mature, fibrous connective tissue stroma and characterized by slow but progressive growth. Very few cases of AOT associated with a dentigerous cyst have been reported in the literature. PubMed and Medline data showed a total of 11 cases of AOT associated with a dentigerous cyst in the literature. We present an additional case of an AOT arising from a dentigerous cyst around the crown of an unerupted upper canine in a 20-year-old female, which was clinically diagnosed as a dentigerous cyst. Histologically, the case showed proliferation of odontogenic epithelium in the form of whorls and islands typical of AOT associated with dentigerous cyst appearing thin reduced enamel like epithelium lining the cystic cavity, described previously. However, it is unclear whether this entity has a more aggressive potential.
Keywords: Adenomatoid odontogenic tumor, dentigerous cyst, impacted tooth, unilocular
|How to cite this article:|
Manjunatha B S, Harsh A, Purohit S, Naga MV. Adenomatoid odontogenic tumor associated with a dentigerous cyst. J Can Res Ther 2015;11:649
| > Introduction|| |
Adenomatoid odontogenic tumor (AOT) is an uncommon tumor of odontogenic origin, composed of odontogenic epithelium in a variety of histological patterns. The lesion is benign (hamartomatous) and non-invasive, with a slow but progressive growth. It accounts for 2-7% of all odontogenic tumors and is less frequent. The epithelial lining of the odontogenic cyst may transform into an odontogenic neoplasm-like ameloblastoma or AOT. ,,, There are very few reports of odontogenic tumors either arising from or associated with odontogenic cysts. According to WHO, the AOT was reclassified as an epithelial odontogenic tumor and was defined as a tumor composed of odontogenic epithelium, presenting a variety of histoarchitectural patterns, embedded in mature connective tissue stroma, and characterized by slow and progressive growth. The epithelial lining of the odontogenic cyst may transform into an odontogenic neoplasm-like ameloblastoma or AOT.  The purpose of this article is to present a rare case of AOT that originated in the wall of a dentigerous cyst.
| > Case report|| |
A 20-year-old female came with the chief complaint of a swelling on the palatal aspect. Intraoral examination revealed a firm well-defined swelling extending from the anterior palatal area behind central incisor extending to the second premolar on the same side. The swelling was associated with mild pain and the maxillary permanent left canine was missing. There was no evidence of any malignancy, and the mucosa was normal and intact.
A computed tomography (CT) revealed a well-defined, unilocular radiolucent lesion associated with an unerupted maxillary left permanent canine extending from the apex of the left central incisor to the distal aspect of the left second premolar [Figure 1]. Based on the clinical and radiographic findings, the differential diagnosis of dentigerous cyst, AOT and odontogenic keratocyst were made. The mass was enucleated completely along with the embedded canine and the specimen was submitted for the histopathological examination [Figure 2]. The excised specimen showed a thin cystic lining of non-keratinized stratified squamous epithelium similar to reduced enamel epithelium [Figure 3] associated with focal areas of intra-luminal proliferating islands consisting of spindle shaped epithelial cells [Figure 4], some arranged in a rosette pattern [Figure 5] and [Figure 6]. The underlying connective tissue was dense composed of thick bundles of collagen fibers along with few epithelial rest cells and blood vessels. A diagnosis of AOT associated with dentigerous cyst was made.
|Figure 1: CT showing a well-defined, unilocular radiolucent lesion with an impacted canine|
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|Figure 2: Photograph showing surgical specimen along with impacted tooth|
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|Figure 3: Photomicrograph showing thin non-keratinized stratified squamous epithelial lining typical of dentigerous cyst (H and E stain ×40)|
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|Figure 4: Photomicrograph showing of non-keratinized stratified squamous epithelial lining of 2-3 cell thickness with areas of luminal proliferation (H and E stain ×100)|
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|Figure 5: Photomicrograph showing proliferation of odontogenic epithelial cells arranged in adenoid and rosette pattern confirming as AOT (H and E stain ×450)|
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|Figure 6: Photomicrograph showing odontogenic epithelial cells arranged in clusters and adenoid pattern (H and E stain ×450)|
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| > Discussion|| |
Adenomatoid odontogenic tumor (AOT) is a relatively uncommon benign odontogenic neoplasm that was first termed as 'adamantinoma' by Ghosh.  Dreibaldt in 1907 described it as 'pseudoadenoameloblastinoma'.  Harbitz in 1915 reported it as 'cystic Adamantoma'. Stafne in 1948, considered it as a distinct entity and the term "Adenomatoid Odontogenic Tumor" was proposed in 1969 by Philipsen and Birn. ,,
AOT is a benign lesion derived from the complex system of dental lamina or its remnant. It has been reported that some odontogenic cysts occur in association with odontogenic tumors.  Because neoplastic and hamartomatous lesions can occur at any stage of odontogenesis, odontogenic tumors with combined features of epithelial and mesenchymal components may arise within the odontogenic cyst.  In the present report, thin cystic lining of dentigerous cyst and intra-luminal proliferation of AOT-like areas were noted in focal areas. Based on these findings, it is hypothesized that AOT like changes in the cyst wall developed in a pre-existing dentigerous cystic lining. Garcia-Pola et al.,  have described the proliferation of an AOT in the epithelial lining of a dentigerous cyst. Tajima et al.,  described an AOT located in the superior portion of the maxillary sinus and speculated that the tumor was derived from a dentigerous cyst. Philipsen et al., ,, also postulated that the follicular type of AOT develops from nests of cells within the dental lamina and, subsequently surrounds the tooth.
A systematic search of Medline and PubMed showed only 11 such cases in the English literature. ,,,,,,,,,, The clinical and other details of all cases are presented in [Table 1]. Out of 11 cases including the present case, the age range of patient was from 8 years to 39 years with the mean age being 17.8 years. The male to female ratio is slightly more in males contrary to AOT, which is common in females. All the previously reported cases were associated with impacted or unerupted tooth. Many of the cases occurred in the maxilla ,,,,,, and two were associated with the maxillary sinus. , One case was seen both in the maxilla, as well as, in the adjacent maxillary sinus.  Of these, only four cases occurred in the posterior region of the jaw ,,, and most of the cases were associated with impacted canine. ,,,,, All previous cases except for one and the present case showed unilocular radiolucency. ,,,,,,,, One case was presented with a well-defined radiopaque mass.  There is an uncertainty whether the lining of an associated cyst represents a true dentigerous cyst, or a cystic change within an AOT or may represent a distinct entity.
|Table 1: Clinical and radiographic details of previously reported cases in the literature|
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According to Marx and Stern, the more appropriate term is adenomatoid odontogenic cyst (AOC). Nevertheless, the present case is mainly cystic with areas of AOT-like proliferations into the lumen, thus supporting the view of Marx and Stern hooking to the terminology of adenomatoid odontogenic cyst (AOC). 
However, it is unclear whether this entity has a more aggressive potential. Most central AOT's occur in a pericoronal relationship with an associated teeth; there is no way to be certain whether the lining of an associated cyst represents a true dentigerous cyst or a secondary cystic change within the AOT.  The AOT and dentigerous cyst are both benign, encapsulated lesions and conservative surgical enucleation or curettage is the treatment of choice.
| > Conclusion|| |
The present report describes a rare case of AOT associated with a dentigerous cyst, highlighting the importance of the histopathological examination in the cystic lesions of the jaw bones. Meticulous histopathological evaluation is thus required in all enucleated cysts, which could contribute to the diagnosis of similar cases as reported in the present study.
| > References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]