|Year : 2016 | Volume
| Issue : 2 | Page : 199-202
CH Lalitha1, Stuti Goyal1, Lakshmikanth Perka2, Srikant Kodangal1
1 Department of Oral Medicine and Radiology, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India
2 Primary Health Centre, Hyderabad, Telangana, India
|Date of Submission||12-Aug-2015|
|Date of Acceptance||21-Nov-2016|
|Date of Web Publication||02-Dec-2016|
C H Lalitha
Department of Oral Medicine and Radiology, Sri Sai College of Dental Surgery, Vikarabad, Telangana
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Ameloblastic fibroma, is a mixed odontogenic tumor, which commonly affects young children under the age of 20 years, with the mandibular premolar-molar region being the most common site of manifestation. This is a case report of a 25-year-old female with a swelling in the right posterior mandibular region since 4 months, which was subsequently diagnosed as ameloblastic fibroma.
Keywords: Ameloblastic fibroma, mandibular neoplasm, odontogenic tumor
|How to cite this article:|
Lalitha C H, Goyal S, Perka L, Kodangal S. Ameloblastic fibroma. J Indian Acad Oral Med Radiol 2016;28:199-202
| Introduction|| |
The ameloblastic fibroma, a mixed odontogenic tumor, is a non-encapsulated tumor that is composed of mesenchymal tissue that resembles the dental papillae and small islands of odontogenic epithelium that resembles the dental lamina.  It is relatively rare and represents only 2% of the odontogenic tumors.  Young children under the age of 20 years are usually affected , with mandibular premolar and molar region being the most common sites of manifestation of the tumor. Radiographically, the presentation varies from a well-defined to poorly-defined unilocular or multilocular radiolucency. It is treated by surgical excision, and the recurrence rate is low. 
| Case Report|| |
A 25-year-old female patient reported to the dental outpatient department at the Government Dental College, Hyderabad, with the chief complaint of swelling in the right lower back tooth region since 4 months. The patient gave a history of gradual increase in the size of the swelling with time, which was neither associated with pain nor with discharge. There was no significant past medical or family history. Patient had previously undergone extraction of the left lower back tooth approximately 2 years ago. There was no history of any tobacco habits.
On extraoral examination [Figure 1] and [Figure 2], face was asymmetric owing to the diffuse swelling on the right lower one-third region of the face, measuring approximately 3.5 × 3.0 cm in size and roughly oval in shape. The swelling extended anteroposteriorly from the corner of the right lip to 2 cm in front of the angle of the mandible and superioinferiorly, 1.5 cm below the alae-tragus line to 0.5 cm below the inferior border of the mandible. The overlying skin was similar to the adjacent skin and showed no visible pulsations. On palpation, the swelling was mildly tender and bony hard in consistency. There were no palpable pulsations. No palpable lymph nodes were present. On intraoral examination [Figure 3], an ill-defined swelling, measuring approximately 2 × 1.5 cm was present in the lingual region of 45, 46, and 47. The swelling extended anteroposteriorly from the distal aspect of 45 to the distal aspect of 47, and superioinferiorly it extended from the marginal gingiva of 46 to the depth of the sulcus. There was visible buccolingual cortical plate expansion, more so on the lingual side. The overlying mucosa was smooth, pale and appeared slightly stretched. There were no visible pulsations. On palpation, the swelling was mildly tender and hard in consistency. There were no palpable pulsations. There was no discharge. On hard tissue examination, 36 tooth was missing. There was vestibular obliteration in relation to 46 tooth region. Chair-side needle aspiration was negative. Pulp vitality test of 44, 45, 46 and 47 showed normal response. A provisional diagnosis of right mandibular odontogenic tumor was given. A differential diagnosis of ameloblastoma, odontogenic myxoma, central giant cell granuloma, dentigerous cyst, traumatic bone cyst was given.
|Figure 1: Profile picture of the patient showing the asymmetry owing to the swelling|
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|Figure 3: Intraoral picture showing the swelling on the lingual aspect of 45,46, and 47|
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The radiographic investigations performed were, orthopantomograph [Figure 4] and right lateral oblique view of the body of the mandible. A well-defined, noncorticated, solitary unilocular radiolucency was seen extending anteroposteriorly in the right mandibular region from 45 to 47 region and superioinferiorly it extended from the root apices of 45 and 46 to approximately 3 mm above the inferior border of the mandible. Incisional biopsy was performed and the histopathological section [Figure 5] showed strands and buds of epithelial cells embedded in a cellular connective tissue stroma. The cells were cuboidal and two cell layers thick, suggestive of ameloblastic fibroma. Subsequently, surgical enucleation and mechanical curettage was performed. The patient is being followed up for any recurrence.
|Figure 4: Orthopantomogram showing a well-defined, noncorticated solitary unilocular radiolucency in 45, 46, and 47 region|
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| Discussion|| |
In 1891, Kruse first described cystic tumors of the mandible, which are known today as ameloblastic fibromas.  Ameloblastic fibroma is a true histologic biphasic tumor because epithelial and mesenchymal components are part of the neoplastic process. It is a circumscribed lesion predominantly located over unerupted molars in young patients. The epithelium and connective tissue recapitulate the cap and the bell stages of odontogenesis. Relative frequency of ameloblastic fibroma ranges between 1.5 and 4.5%. According to Reichart and Philipsen, male to female ratio was 1.4:1. Mean age of occurrence is 14.8 years with a range of 0.5 to 62 years. It is a slow growing tumor which is commonly located in the mandibular posterior area and is often associated with an impacted tooth. If ameloblastic fibroma is near the surface, slight buccal and lingual cortical plate expansion is evident. 
According to the World Health Organization (1992), the ameloblastic fibroma is clearly a neoplasm of odontogenic origin with an epithelial and an ectomesenchymal component. The biological behavior of ameloblastic fibroma shares the nature between hamartoma and true neoplasm.  Cahn and Blum postulated that an ameloblastic fibroma could develop eventually into an odontoma if the lesion is allowed to remain. They believed that the only difference between the ameloblastic fibroma and the odontoma is the patient's age and the degree of maturation of the lesions. This would imply that all ameloblastic fibromas, ameloblastic fibrodentinomas and ameloblastic fibrodontomes, merely represent various stages of the same lesion and mature over time ultimately resulting in the formation of an odontoma. However, this "continuum concept" has not been widely accepted as recent evidence suggests that ameloblastic fibroma exhibits a high recurrent rate, and in some cases, malignant transformation.  Pathogenetically, the epithelial components, the ameloblast-like cells, are too primitive to induce the cells of the ectomesenchyme.
Radiolographically, ameloblastic fibroma is commonly located near the crest of the alveolar process or in a follicular relationship with an unerupted tooth or it may arise in a area where a tooth failed to erupt. This feature was absent in our case. The borders of ameloblastic fibroma are well defined and corticated. Commonly unilocular, but may be multilocular with indistinct curved septa. It is sometimes associated with expanded but intact cortical plates, unerupted, or displaced tooth.  Similar findings are seen in computed tomography (CT); however, when the CT window is adjusted for bone, a very thin layer of subperiosteal new bone is found in the same areas, appearing to be burnt out or perforated in plain radiographs. 
Histologically, the ameloblastic fibroma is characterized by the proliferation of odontogenic epithelium supported by a primitive mesenchymal connective tissue stroma. The epithelium presents as nests, buds, and cords of cuboidal or columnar cells, which may develop a central portion resembling a stellate reticulum. The cell rich mesenchymal component closely resembles the dental papilla of the developing tooth germ. The ameloblastic fibroma contains no calcified tissue elements. Mitoses should not be a feature of ameloblastic fibroma. The presence of mitosis should expand the differential diagnosis to include malignant entities such as ameloblastic fibrosarcoma. 
Treatment for ameloblastic fibroma is described as conservative excision. Reichart and Philipsen proposed that the innocuous behavior of the lesion does not justify aggressive initial treatment but rather meticulous surgical enucleation with close clinical follow-up.  In general, a conservative approach, such as enucleation with curettage of the surrounding bone, should be applied for young patients. While uncommon, the possibility of malignant transformation of ameloblastic fibroma into ameloblastic fibrosarcoma is well documented and the recurrence rate of ameloblastic fibroma found by Trodahl et al. was 43.5%; on the other hand, by Zallen et al. it was 18.3% after reviewing literature with 85 cases of ameloblastic fibroma. An aggressive surgical treatment is, therefore, suggested by some authors because of the possibility of malignant transformation of an ameloblastic fibroma to an ameloblastic fibrosarcoma. No matter what the reason of recurrence is, a long term follow-up is necessary. 
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]