Adenomatoid odontogenic tumor AOT , a benign hamartomatous lesion of odontogenic origin, is an uncommon tumor which affects mainly females in the second decade. This lesion is most commonly associated with an impacted maxillary canine. This paper reported a case of AOT, in a year-old female, associated with an impacted maxillary left lateral incisor. The evolution of this tumor was followed over 36 months and 24 months after excision. Dreibaldt in was the first to describe adenomatoid odontogenic tumor AOT , which is an uncommon benign epithelial lesion of odontogenic origin known as a pseudo-adenoameloblastoma [ 1 ]. In the World Health Organization classification of odontogenic tumors established in , AOT was mentioned [ 1 , 4 ] as a mixed odontogenic neoplasm, in other words, an epithelial tumor with an inductive effect on the odontogenic mesenchyme [ 1 , 5 ].
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Adenomatoid odontogenic tumor AOT is a rare odontogenic tumor which is often misdiagnosed as odontogenic cyst. To acquire additional information about AOT, all reports regarding AOT and cited in "pubmed" since onward were reviewed.
It is predominantly found in young and female patients, located more often in the maxilla in most cases associated with an uneruppted permanent tooth. For radiological diagnose the intraoral periapical radiograph seems to be more useful than panoramic. However, AOT frequently resemble other odontogenic lesions such as dentigerous cysts or ameloblastoma. Immunohistochemically AOT is characterized by positive reactions with certain cytokeratins.
Treatment is conservative and the prognosis is excellent. For illustration a rare case of an AOT in the mandible is presented. Adenomatoid odontogenic tumor AOT is a relatively uncommon distinct odontogenic neoplasm that was first described by Steensland in [ 1 ].
However, a variety of terms have been used to describe this tumor. Unal et al [ 2 ] produced a list containing all nomenclatures for AOT reported in the literatures. Many different names like adenoameloblastoma, ameloblastic adenomatoid tumor, adamantinoma, epithelioma adamantinum or teratomatous odontoma have been used before to define the lesion currently called AOT. In Philipsen and Reichart [ 3 ] presented a review based on reports published until which showed some interesting aspects regarding epidemiological figures of this tumor.
Since then numerous case reports of AOT have been published. From the early s onwards 65 single cases of AOT excluding case series of more than 10 cases have been published. The mean age was Regarding the various case series published in the literature [e.
The tumor is most often diagnosed in the second decade of life and women are about twice as many affected than men. The AOT is over two times more located in the maxilla than in the mandible and the anterior jaw is much more affected than the posterior area.
According to Philipsen and Reichart [ 3 ] the AOT appears in three clinico-topographic variants: follicular, extrafollicular and peripheral.
Clinical features generally focus on complaints regarding a missing tooth. The lesion usually present as asymptomatic swelling which is slowly growing and often associated with an unerupted tooth.
However, the rare peripheral variant occurs primarily in the gingival tissue of tooth-bearing areas [ 9 ]. Unerupted permanent canine are the theeth most often involved in AOTs. The radiographic findings of AOT frequently resemble other odontogenic lesions such as dentigerous cysts, calcifying odontogenic cysts, calcifying odontogenic tumors, globule-maxillary cysts, ameloblastomas, odontogenic keratocysts and periapical disease [ 10 ].
Whereas the follicular variant shows a well-circumscribed unilocular radiolucency associated with the crown and often part of the root of an unerupted tooth, the radiolucency of the extrafollicular type is located between, above or superimposed upon the roots of erupted permanent teeth [ 3 ].
Displacement of neighbouring teeth due to tumor expansion is much more common than root resorptions. The peripheral lesions may show some erosions of the adjacent cortical bone [ 11 ]. Comparing diagnostic arruracy between intraoral periapical and panoramic radiographs Dare et al. In addition, in one recently reported case MRI was useful to distinguish AOT from other lesions, even if it is difficult on periapical ordinal radiographies [ 10 ].
Remarkably, all variants of AOT show identical histology. The histological typing of the WHO defined the AOT as a tumor of odontogenic epithelium with duct-like structures and with varying degrees of inductive change in the connective tissue.
The tumor may be partly cystic, and in some cases the solid lesion may be present only as masses in the wall of a large cyst [ 14 ]. Moreover, eosinophilic, uncalcified, amorphous material can be found and is called "tumor droplets". Some tumor droplets show a homogenous matrix whereas most tumor droplets reveal electron-dense plaques [ 15 ]. Interestingly, there are a few reports about pigmented cells in AOT. However, all of these reported lesions did not show macroscopically visible pigmentation.
Racial pigmentation probably plays an important role in such cases [ 16 , 17 ]. During the last few years several studies have been published dealing with the immunhistological properties of AOT. Recently, Crivelini et al. Positive reactions for amelogenin in limited areas in AOT are also reported as well as in ameloblasts and in the immature enamel matrix [ 20 ]. Interestingly, Takahashi et al. Finally, Gao et al.
Whereas cementifying fibromas, dentinomas and compound odontomas demonstrated a positive reaction, all AOT as well as ameloblastomas and calcifying epithelial odontogenic tumors were negative. Conservative surgical enucleation is the treatment modality of choice. For periodontal intrabony defects caused by AOT guided tissue regeneration with membrane technique is suggested after complete removal of the tumor [ 23 ].
Recurrence of AOT is exceptionally rare. Only three cases in Japanese patients are reported in which the recurrence of this tumor occurred [ 24 ]. Therefore, the prognosis is excellent. A year-old man was referred by his general dental practitioner.
One year ago the dentist diagnosed a cyst with a ectopic lower right canine tooth by an x-ray. Beside an uneventful medical history the patient presented no conspicuous intraoral clinical findings except the absence of the tooth Radiologically, he showed a 3 cm unicystic radiolucent image with a comparatively clear demarcation. The tooth 43 was located on the floor of this process.
No resorption of the root apices was observed Fig. Panoramic radiograph before therapy. Unicystic radiolucent lesion in the lawer right jaw with a comparatively clear demarcation. The tooth 43 is located on the floor of this process. There are no resorption of the root apices.
Under general anesthesia the lesion was enucleated and afterwards filled with pelvic spongiosa. Separating the lesion from mandibular bone caused no problems. The postoperative course was uneventful. After the operation, the specimen was fixed in 4 per cent formal saline and prepared for histological examination.
Some sections were stained with haematoxylin-eosin. Histologically, the tumor is solid and there is a cyst formation Fig.
The epithelium is in the form of whorled masses of spindle cells as well as sheets and plexiform strands. Rings of columnar cells give rise to duct-like appearance Fig. Calcification is sometimes seen and may be extensive Fig. Nodular aggregates of cells. Half a year after surgery a clinical and radiographic follow-up examination was performed. There was no evidence of recurrence and no apical resorption of the adjacent teeth could be observed Fig. With respect to the age of the patient and the localization of the AOT in the lower jaw, the reported case is a rare example of this tumor entity.
Beyond it our case supports the above mentioned general description of AOTs. All authors disclaim any financial or non-financial interests or commercial associations that might pose or create a conflict of interest with information presented in this manuscript.
SB and AZ carried out the pathohistological investigations and participated in creating this part of the manuscript. All authors were involved in revising the manuscript critically and have given final approval of the version to be published. National Center for Biotechnology Information , U.
Journal List Head Face Med v. Head Face Med. Published online Aug Author information Article notes Copyright and License information Disclaimer. Corresponding author. Received Mar 25; Accepted Aug This article has been cited by other articles in PMC.
Abstract Adenomatoid odontogenic tumor AOT is a rare odontogenic tumor which is often misdiagnosed as odontogenic cyst. Keywords: adenomatoid odontogenic tumor, review. Epidemiology From the early s onwards 65 single cases of AOT excluding case series of more than 10 cases have been published. Clinical features Clinical features generally focus on complaints regarding a missing tooth. Radiographic features The radiographic findings of AOT frequently resemble other odontogenic lesions such as dentigerous cysts, calcifying odontogenic cysts, calcifying odontogenic tumors, globule-maxillary cysts, ameloblastomas, odontogenic keratocysts and periapical disease [ 10 ].
Pathohistological features Remarkably, all variants of AOT show identical histology. Immunhistological features During the last few years several studies have been published dealing with the immunhistological properties of AOT. Treatment and prognosis Conservative surgical enucleation is the treatment modality of choice. Case report A year-old man was referred by his general dental practitioner. Open in a separate window. Figure 1. Figure 2. Figure 3. Figure 4. Figure 5.
Adenomatoid odontogenic tumor of the mandible: review of the literature and report of a rare case
The adenomatoid odontogenic tumor AOT was formerly considered to be a variant of the ameloblastoma and was designated as adenoameloblastoma. Though this lesion shows pathognomic histological features, few overlapping patterns of the odontogenic tumors may be seen. AOT may infrequently show additional areas resembling to calcifying epithelial odontogenic tumor. Long-term follow-up research is need of the hour for such hybrid histological combination effect on the locally aggressive nature of the lesion.
2015, Number 3
Adenomatoid odontogenic tumor AOT is an uncommon tumor of odontogenic origin, characterized histologically by the formation of ductlike structures with amyloid-like deposits. Histogenesis of AOT is still uncertain and it is often considered as a hamartomatous lesion rather than a true neoplasm. AOT has a benign behavior and conservative surgical enucleation or curettage is sufficient. We report a case of AOT in a year-old female who presented with left-sided jaw swelling with tooth resorption.
Adenomatoid odontogenic tumor: A unique report with histological diversity
Adenomatoid odontogenic tumor AOT is a rare odontogenic tumor which is often misdiagnosed as odontogenic cyst. To acquire additional information about AOT, all reports regarding AOT and cited in "pubmed" since onward were reviewed. It is predominantly found in young and female patients, located more often in the maxilla in most cases associated with an uneruppted permanent tooth. For radiological diagnose the intraoral periapical radiograph seems to be more useful than panoramic. However, AOT frequently resemble other odontogenic lesions such as dentigerous cysts or ameloblastoma.