|Year : 2019 | Volume
| Issue : 2 | Page : 56-59
Adenomatoid odontogenic tumor of the maxilla
Manisha Sahu, Hema Suryawanshi
Department of Oral Pathology, CDCRI, Rajnandgaon, Chhattisgarh, India
|Date of Web Publication||18-Nov-2019|
Dr. Manisha Sahu
Department of Oral Pathology, CDCRI, Rajnandgaon, Chhattisgarh
Source of Support: None, Conflict of Interest: None
Adenomatoid odontogenic tumor (AOT) is a distinct odontogenic tumor, which accounts for about 3%–7% of all odontogenic tumors. It is a benign (hamartomatous), noninvasive lesion with slow but progressive growth. It is predominantly found in young female patients, located more often in the maxilla associated with an unerupted permanent tooth. Treatment is conservative surgical excision, and the prognosis is excellent. Here, we report a case of AOT in the maxilla in a young male aged 14 years.
Keywords: Adenomatoid odontogenic tumor, impacted premolar, maxilla
|How to cite this article:|
Sahu M, Suryawanshi H. Adenomatoid odontogenic tumor of the maxilla. Indian J Oral Health Res 2019;5:56-9
| Introduction|| |
Adenomatoid odontogenic tumor (AOT) is a benign relatively uncommon neoplasm that comprises only 0.1% of tumors of head and neck and 3%–7% of all odontogenic tumors.
AOT was first described by Steensland in 1905 and then by Dreiblatt in 1907, as a pseudo-adenoameloblastoma. Over the years, a variety of terminologies have been used to designate this extremely fascinating entity such as adenoameloblastoma, adenoameloblastic odontoma, epithelial tumor associated with ameloblastic adenomatoid tumor, developmental cysts, and adenomatoid or pseudo-adenomatous ameloblastoma. In 1969, Philipsen and Birn introduced the term AOT, indicating that it did not constitute a variety of ameloblastoma, which was adopted by the WHO classification in 1971.
AOT is also called “two-thirds tumor” because two-thirds occur in young females, two-thirds of adenomatoid tumors occur in the maxilla, two-thirds of the cases are associated with unerupted teeth, and two-thirds of the affected teeth are canines. AOT presents as three clinical subtypes, all with identical histology: (1) follicular type (in 73% of AOT), centrally located, with a radiolucent unilocular cystic area associated with an unerupted or impacted tooth (usually canine), simulating the image of a dentigerous cyst; (2) the extrafollicular variant (24%), likewise with a central location, but unrelated to any dental structure and may be confused with periapical cysts and other cystic or tumoral lesions of the maxilla; (3) finally, the peripheral form is the most infrequent (3%), affects the gingival mucosa, and is often preoperatively classified as a fibrous epulis or gingival fibroma.
| Case Report|| |
A 14-year-old male reported to the dental college with the complaint of swelling in the upper left front region of the jaw for 1 month. History of the present illness revealed that initially, the swelling was small in size, and gradually, it increased to reach up to the present size. It was not associated with any pain or discharge with no history of trauma associated with it. The patient's social, family, and habit histories were noncontributory.
Extraoral examination revealed mild facial asymmetry on the left side. Swelling was diffuse [Figure 1] which extended anteroposteriorly from left ala of nose to 2 cm posteriorly and superoinferiorly 2 cm below the left lower eyelid to the left corner of the mouth. On palpation, the swelling was bony hard, nonfluctuant, nontender and showed no evidence of discharge on digital pressure. There was no regional lymphadenopathy.
Intraoral examination revealed a solitary bony hard swelling extending from the permanent left maxillary lateral incisor (22) to the permanent left maxillary first molar (26) causing buccal expansion with obliteration of the buccal vestibule. Deciduous first molar was retained and first premolar (24) was missing. Overlying mucosa appeared blanched with Grade II mobility of deciduous first molar [Figure 2].
|Figure 2: Intraoral photograph – Diffuse swelling causing obliteration of buccal vestibule|
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A panoramic radiograph demonstrated a well-demarcated unilocular radiolucent lesion measuring about 2.5 cm × 2 cm extending from distal aspect of 23 to mesial aspect of 26. There was displacement of 23 and 25. 24 was impacted [Figure 3].
|Figure 3: Orthopantomogram showing impacted maxillary left first premolar in a well-defined radiolucency|
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Complete surgical excision of the lesion was done with removal of impacted 24, and the specimen was sent for the histopathological examination. Grossly, the surgical specimen was single attached to the tooth, tan-colored, roughly spherical measuring 2.5 cm × 2 cm in diameter. Cut surface showed a cystic space with the crown of 24 embedded in it along with soft tissue nodules surrounded by a thick capsule [Figure 4].
|Figure 4: Gross examination revealing a tan-colored, roughly spherical-shaped tumor mass with embedded maxillary left first premolar|
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Hematoxylin and eosin-stained sections under a microscope revealed thick fibrous capsule surrounding the nodules of epithelium. Tumor mass composed of spindle-shaped cells forming sheets and whorled masses and solid nodules of cuboidal epithelial cells forming rosette-like structures in a scant connective tissue stroma was seen. Furthermore, areas with varying number of duct-like structures with lumina of varying size that are lined by a single layer of cuboidal–columnar epithelial cells that have nuclei polarized away from the lumen. Some areas showed cells arranged in multiple layers. In between each of the layers, a band of eosinophilic material gave a typical rosette pattern [Figure 5], [Figure 6], [Figure 7].
|Figure 5: Photomicrograph illustrating epithelial cells arranged in various patterns such as ductal or tubular, rosette, sheets, and nest with surrounding fibrous capsule (H and E stain, ×4)|
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|Figure 6: Photomicrograph illustrating a highly cellular tumor mass forming nests of rosette-like and duct-like structures (H and E stain, ×10)|
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|Figure 7: Photomicrograph illustrating rosette pattern (H and E stain, ×40)|
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All features suggested final diagnosis of AOT.
| Discussion|| |
AOT is a benign, noninvasive odontogenic lesion showing slow growth. The histogenesis of AOT is still uncertain; however, the authors agree with its odontogenic origin because this tumor occurs exclusively in toothed areas and is frequently associated with impacted teeth, having cytological components similar to those of the enamel organ, dental lamina, or its remnants.
AOT may be present with other concomitant lesions, giving rise to so-called hybrid lesions or combined tumors. There are reports of presentation of AOT combined with calcifying epithelial odontogenic tumor, odontoma, and dentigerous cyst., However, debate as to whether it represents anomalous hamartomatous growth or a true benign neoplasm is not yet settled.
The present case was seen in a male; however, according to the literature, the lesion has female predilection. The patient was 14 years old within the age group (second decade) of higher incidence. It was seen in maxilla which is a usual site of presentation for an AOT. Literature analysis reveals canines to be the most common teeth associated with the follicular AOT; however, in our case, it was associated with premolar. Usually, AOT leads to displacement of adjacent teeth, which was seen in our case discussed above. Radiographic findings observed in the case presented here is peculiar to the follicular variant of AOT, presenting as unilocular radiolucent, circumscribed, cortical limits, associated with the crown of an unerupted tooth.
AOT is usually surrounded by a well-developed connective tissue capsule. Microscopically, it is composed of spindle epithelial cells, forming nests, cords, or cell masses, in a little fibrous stroma. Rosettes can be formed from the epithelial cells around a central space that may be empty or contain eosinophilic material, which can stain as amyloid. The characteristic duct-like structures are lined by a single row of columnar epithelial cells, the nuclei of which are polarized away from the central lumen. Small focus of calcification may be scattered throughout the tumor, being interpreted as abortive formation of enamel.,
The treatment of choice consists of a conservative surgical approach with total enucleation of the lesion because they are benign encapsulated neoplasms with low recurrence rate.
Immunohistochemically, the classical AOT phenotype is characterized by a cytokeratin (CK) profile similar to follicular cyst and/or oral or gingival epithelium based on positive staining with CK5, CK17, and CK19. On the other hand, classical AOT is negative for CK4, CK10, CK13, and CK18. CK14 expression was also detected in AOT indicating its origin from reduced dental epithelium. In an unconventional case reported by Shah et al., expression of PCNA and p53 was positive and suggested that such aggressive cases should be considered as true benign neoplasm.
| Conclusion|| |
Deciduous teeth retained for longer duration with unerupted succeeding permanent teeth associated with swelling should be considered for odontogenic lesions. Although AOT is an uncommon lesion, it can be easily identified from its characteristic histopathological appearance. It is necessary to report odontogenic lesions for epidemiological studies, which will further increase the knowledge about clinical behavior and evolution of this tumor.
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.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]