Adenometoidodontogenictumour : A rare case presentation

Adenomatoidodontogenic tumor (AOT) is a rare, slow-growing, benign tumor of odontogenic origin. It accounts for about 1% to 9% of all odontogenic tumors.

Adenometoidodontogenictumour : A rare case presentation
Adenomatoidodontogenic tumor (AOT)

India, June 12: 


Adenomatoidodontogenic tumor (AOT) is a rare, slow-growing, benign tumor of odontogenic origin. It accounts for about 1% to 9% of all odontogenic tumors. It is most commonly found in young female patients, located more often in the maxilla. Herein, we report a case of AOT in 18 year old female presented with swelling in left anterior maxilla.


Adenomatoidodontogenic tumor (AOT) is a relatively uncommon distinct odontogenic neoplasm that was first described by Steensland in 1905 [1]. Philpsen and Birn (1971) proposed the widely accepted and currently used name, adenomatoidodontogenic tumor [2].Two third of this tumor occur in young females, two-thirds of the cases are associated with un-erupted teeth, and two-thirds of the affected teeth are canines, so this tumor is also called as ‘two-thirds tumor’ [3].

In this case report we present an AOT causing left upper jaw swelling with impacted maxillary lateral incisor and canine.


A eighteen years old female patient presented in dental department of our institution with a swelling on her left upper jaw since 2 to 3 months. The swelling had gradually increased in size and was associated with mild pain.

Extra-oral, physical examination revealed a single diffuse swelling in the left anterior maxillary region measuring about 5 cm × 4 cm in size,nasolabial fold is obliterated. Overlying skin was tense associated with no change in overlying skin color and have no discharging sinuses. On palpation, the swelling was firm to hard in consistency, non-tender, immobile with diffuse margins.

On intra-oral examination, a single, well-circumscribed swelling with a smooth surface was present in the buccal and palatal aspect of the left upper anterior maxillary region, resulting in obliteration of thegingivobuccal sulcus.Deciduous left maxillary lateral incisor and canine teeth were present. The permanent maxillary left lateral incisor and canine teeth were missing.

Radiograph of the left maxillary anterior region and an orthopantomaograph (OPG) revealed a well-circumscribed unilocular radiolucentlesion with sclerotic margin associated with an impacted left maxillary lateral incisor and canine teeth. Focal specks of calcification in the radiolucent area were present. .

The lesion was enucleated under general anaesthesia and sent for histopathological examination. The tumor was received in two containers labeled anterior and posterior regions. Multiple grey brown soft tissue pieces together measuring 2.3X2X0.5 cm and 2.8X1.8X0.2 cm respectively were received in the containers. On cut section no cyst were identified.Microscopically, the lesion revealed many nodular structure that forming nests and whorls, stroma shows many congested blood vessel [Figure 1].Some glands like structures are seen in the epithelial nodule which is lined by tall columnar cell with nuclei pointing away from the basement membrane [figure 2].  Focal areas of calcification also seen [Figure 2]. Overall features were diagnostic for adenomatoidodontogenic tumor.

Figure 1: Photomicrograph showing many nodular arrangement of cells with congested blood vessel in the stroma(100X).


Figure 2: Photomicrograph showing some glandular structures lined by tall columnar cell in the epithelial nodule along with foci of calcification (200X).


AOT is uncommon benign, hamartomatous,noninvasive,odontogenic tumor with a relative frequency of 3% of all odontogenic tumorsfollowed by odontoma, periapicalcemental dysplasia (cementoma), myxoma, and ameloblastoma[4]. It usually affects young female(female to male ratio beings 1.9:1) with the mean age of presentation beings between eight and twenty-five years [5, 6, 7]. In our case, the patient was 18 years of age, which was in concordance with the literature.

Most of the cases reported in the literature were in the maxilla and affectedanterior segment most commonly. They were associated with unerupted maxillary canine tooth [6]. The case we report here was also similar with the tumor being associated with an impacted maxillary lateral incisor and canine.

There are three clinicopathologic variants of AOT, namely intraosseus follicular, intraosseusextrafollicular and peripheral; all with identical histology. The follicular type is a central intraosseus lesion associated with an impacted tooth, while extrafollicularintraosseus AOT has no relation with an unerupted tooth. In spite of this, it is often located between, above or superimposed upon the roots of adjacent erupted teeth. The peripheral variant appears as a gingival fibroma or epulis attached to the labial gingival [5, 9, 10].

The follicular and extrafollicular variants account for 96% of all AOTs (of which 71% are follicular)[4].Follicular and extrafollicular variants together are more commonly found in the maxilla.  The present case was also anintraosseus follicular lesion as it was associated with impacted teeth.

AOT is a very slow growing lesion. The continuous slow growth of the lesion may cause cortical plate expansion leading to a painless hard swelling, asymmetry of the face and displacement of the teeth [11]. Delayed eruption of a permanent tooth or a regional swelling of the jaw may be the first symptom. Pain or other neurologic signs are not characteristic but in our case, the patient had painful slow growing tumor since 2 to 3 months.

Radiographically, intraosseous AOT has distinct features. It usually appears as a pericoronal well‑circumscribed unilocular, radiolucent or radiopaque‑radiolucent mixed lesion with well‑defined corticated or sclerotic border. It usually surrounds an unerupted tooth. It may contain multiple minute variable shaped calcifications or radiopaque foci. These may appear like a ‘cluster of small pebbles’ [11]. These calcified deposits are seen in approximately 78% of the lesions [12, 13]. These radiopaque components are also seen in our case.

All the variants of AOT show identical histological features[14].WHO has described AOT as a tumor of odontogenic epithelium with duct‑like structures and with varying degrees of inductive change in the connective tissue [15]. It is usually surrounded by a well‑developed connective tissue capsule. It may present as a solid mass, a single large cystic space, or as numerous small cystic spaces [15]. The tumor is composed of spindle‑shaped or polygonal cells forming sheets and whorled masses in a scant connective tissue stroma. Amorphous eosinophilic material is seen between the epithelial cells, as well as in the center of the rosette‑like structures. 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, as was evident in the present case also. The lumen may be empty or may contain amorphous eosinophilic material[5, 9]. Dystrophic calcification in varying amounts is usually encountered in most AOTs within the lumina of the duct‑like structures, scattered among epithelial masses or in the stroma.

The surgical management of this tumor is enucleation along with the associated impacted tooth and simple curettage[12].  Conservative treatment is adequate because the tumor is well encapsulated, and easily separated from the bone. The surgical specimen may be solid or cystic. The recurrence rate is as low as 0.2% [13-14]. The prognosis is excellent in majority of the cases. The patient in the present discussion has been on regular follow‑up since 6 months after surgery and there has been no recurrence.


AOT is a rare slow‑growing painless, noninvasive tumor, often misdiagnosed as an odontogenic cyst.Persistence of deciduous teeth for a longer duration and unerupted succeeding permanent teeth, when associated with a swelling, should be investigated for odontogenic lesions. For diagnosis of odontogenic lesions, conventional radiographs and histology of the tumor play a major role as radiologymay sometimes leads to an erroneous diagnosis.


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Figure 1: Photomicrograph showing many nodular arrangement of cells with congested blood vessel in the stroma(100X).

Figure 2: Photomicrograph showing some glandular structures lined by tall columnar cell in the epithelial nodule along with foci of calcification (200X).

Satya Dutta, Sonia Hasija,Pawan Singh, ShilpaBairwa,ShivaniKalhan, shilpaTomar. Department of Pathology, SHKM, Nalhar, Mewat, Haryana

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