Adenomatoid odontogenic tumor: a case report

Aim: adenomatoid odontogenic tumor (AOT) is an uncommon tumor of odontogenic origin, constituting only 3% of all odontogenic tumors. By some authors it is regarded as a true benign, non-aggressive non-invasive neoplasm and by others as a developmental hamartomatous odontogenic growth. Based on clinical and radiologic findings the AOT can be subdivided into three variants: follicular (or pericoronal) 70,8%, extrafollicular (or extracoronal) 26,8% and peripheral (or gingival) 2,3%. We report a case in which surgical and orthodontic treatment helped to maintain an impacted mandibular canine associated with an AOT in an adolescent boy. A 15-year-old male presented on 12 November 2009 at the Dentistry Unit of Sant’Andrea Hospital of Rome, with a small swelling in the vestibular area of the left mandibular canine region with persistence of the deciduous canine. Medical history was insignificant and the patient was in good general health with no history of trauma or pain. The nodular swelling had well-defined margins with normal overlying mucosa. On palpation the swelling was bony hard and non-tender. The orthopantomogram revealed an impacted canine tooth with a relatively-defined radiolucent lesion in association with the crown. Under local anesthesia the lesion was completely removed after separating the capsule from the bone and incising it off the canine surface. Minimal bone removal was done with a rose bur. The apex of the root was not involved by the lesion. The wound was irrigated and the flap was sutured in the previous position after the bracket bonding on the exposed crown of the canine. Histological findings were diagnostic of a follicular variant of AOT and it was decided not to remove the tooth in view of the benign nature of the lesion and the rare chance of recurrence. Now the patient is under orthodontic treatment. Discussion: the AOT frequently appears as a unilocular radiolucent lesion that is well circumscribed lateral to or containing an impacted tooth. In approximately two thirds of the cases radiopaque foci have been found . AOT is characterized histologically by the presence of a well-developed fibrous connective tissue capsule, solid nodules of cuboidal or columnar cells of odontogenic epithelium forming nests or rosette-like structures with minimal stromal connective tissue. Between the epithelial cells, eosinophilic amorphous material and globular masses of calcified substances were also present. Conspicuous within the cellular area were structures of tubular or duct-like shapes giving it the adenomatoid appearance. Occasional calcifications have a cementum- or dentine-like appearance. Conservative surgical enucleation and curettage has proven the treatment of choice. Conclusion: in view of the completely benign behaviour of AOT extraction of the permanent dentition in adolescents is not the best indication for the patient especially if it is aesthetically of functionally strategic.