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   Table of Contents    
CASE REPORT
Year : 2021  |  Volume : 25  |  Issue : 5  |  Page : 438-442  

Ameloblastic fibro-odontoma or complex odontoma masquerading as gingival enlargement


1 Department of Oral Pathology and Microbiology, Dental College, Regional Institute of Medical Sciences, Imphal, Manipur, India
2 Department of Oral and Maxillofacial Surgery, Dental College, Regional Institute of Medical Sciences, Imphal, Manipur, India
3 Department of Oral Medicine and Radiology, Dental College, Regional Institute of Medical Sciences, Imphal, Manipur, India

Date of Submission18-Nov-2020
Date of Decision09-Feb-2021
Date of Acceptance08-Mar-2021
Date of Web Publication01-Sep-2021

Correspondence Address:
Doddabasavaiah Basavapur Nandini
Department of Oral Pathology and Microbiology, Dental College, Regional Institute of Medical Sciences, Imphal, Manipur
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jisp.jisp_778_20

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   Abstract 


Ameloblastic fibro-odontoma is a rare tumor affecting the pediatric population and young adults. The World Health Organization (WHO) in 2005 defined it as “A neoplasm composed of proliferating odontogenic epithelium in a cellular ectomesenchymal tissue with varying degrees of inductive changes and dental hard tissue formation.” There exists a controversy on its histogenesis designating it as a hamartoma (developing complex odontoma [CO]) or a true neoplasm since both the lesions appear similar histologically. Recently, the WHO in 2017 has clubbed both these lesions as the same entity. Most cases are reported in males and in mandible, while cases in maxilla are scarce. This article describes a recurrence of a previously reported case of ameloblastic fibroma which showed maturation into AFO or CO in a girl aged 6 years in the posterior maxilla. This case is reported due to its rarity and a brief review with differential diagnosis is also discussed.

Keywords: Ameloblastic fibroma, ameloblastic fibro-odontoma, clinical features, complex odontoma, differential diagnosis, hamartoma, histopathology, maxilla, mixed odontogenic tumor, radiological features


How to cite this article:
Nandini DB, Reddy PB, Singh WR, Singh KS. Ameloblastic fibro-odontoma or complex odontoma masquerading as gingival enlargement. J Indian Soc Periodontol 2021;25:438-42

How to cite this URL:
Nandini DB, Reddy PB, Singh WR, Singh KS. Ameloblastic fibro-odontoma or complex odontoma masquerading as gingival enlargement. J Indian Soc Periodontol [serial online] 2021 [cited 2021 Nov 27];25:438-42. Available from: https://www.jisponline.com/text.asp?2021/25/5/438/325010




   Introduction Top


Ameloblastic fibro-odontoma (AFO) is a benign odontogenic tumor. It arises from the odontogenic epithelium and ectomesenchyme and identified by the presence of pulp, dentin, enamel, cementum, and odontogenic epithelial islands. It is a well-demarcated, slow-growing, expansile, painless lesion commonly affecting the children and young adults. It is often accompanied with an unerupted or misplaced tooth. Conservative surgery is the suggested treatment. The term “AFO” was given by Hooker since this lesion showed characteristics of ameloblastic fibroma (AF) and complex odontoma (CO) histologically.[1] AFO closely resembles ameloblastic fibrodentinoma (AFD) histologically except for the presence of enamel in AFO.[2]

The World Health Organization (WHO) in 2005 discussed AFO and AFD as separate lesions, while in the WHO 2017 classification, these entities have been grouped under odontoma.[3] This report describes a case of AFO or CO in a girl of 6 years in the posterior maxilla.


   Case Report Top


Parents of a 6 year old girl reported to the department complaining of mild pain and swelling of gums in the right maxillary molar region. The lesion was small to begin with and had slowly progressed to the present size in the past 18 months. History revealed that the patient had visited a local dentist 1 year back and a biopsy was performed which was reported as ameloblastic fibroma; however, previous radiographs could not be accessed. Extraoral examination showed slight facial asymmetry on the right side of the face [Figure 1]. A solitary gingival swelling was evident in the right maxillary posterior region extending from the primary first molar tooth to the maxillary tuberosity area intraorally. Buccal and lingual cortical expansion was evident. The maxillary primary second molar and the permanent first molar were missing although a cusp-like structure was evident clinically through the enlarged gingival tissue [Figure 2]. On palpation, the lesion was firm to hard, reducible, and mild tenderness was elicited.
Figure 1: Extraoral photograph showing slight facial asymmetry

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Figure 2: Photograph showing a gingival swelling in the right maxillary posterior regionextendingfromtheprimaryfirstmolartothemaxillarytuberosityarea

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Orthopantomograph and lateral skull radiograph showed a mixed radiolucent lesion with multiple radiopaque foci in the right maxillary posterior region. The right premolars, first molar, and primary second molar were displaced superiorly [Figure 3]a and [Figure 3]b. Computed tomography showed a well-delineated, expansile, hypodense mass with sclerotic border containing multiple radiodense foci resembling a “cluster of pebbles” in posterior maxilla. Posteroinferior border of the lesion revealed bone resorption [Figure 4]a, [Figure 4]b, [Figure 4]c, [Figure 4]d. The left-sided deviated nasal septum and left maxillary sinusitis were noted. Mucosal thickening of left maxillary sinus with reduced volume of right maxillary sinus was also evident.
Figure 3: A mixed radiolucent lesion with multiple radiopaque foci evident in the right maxillary posterior region. The right maxillary primary second molar and the permanent first molar, first and second premolars are displaced superiorly. Orthopantomograph (a); lateral skull radiograph (b)

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Figure 4: Computed tomography showing a solitary, well-circumscribed, hypodense lesion in the right maxillary posterior region with multiple radiodense foci. Three-dimensional reconstruction (a); coronal section (b and c); axial section (d)

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The lesion was diagnosed as AFO based on the history and previous biopsy report. Surgical enucleation was done under general anesthesia. The tissue was sent for histopathologic examination. The deciduous second molar was removed, while the permanent teeth were retained to promote normal eruption and recurrence is not found on follow-up.

Gross tissue specimen was white to cream in color, largest bit measured 1 cm × 1.7 cm × 1.6 cm in dimension, hard in consistency, and showed a nodular surface [Figure 5]. The tissue sections revealed odontogenic epithelium with mineralized tissue [Figure 6]a and primitive ectomesenchyme that resembled the dental papilla focally [Figure 6]b. Multiple irregular conglomerate masses of dentin-like tissue, occasionally enamel matrix, enamel spaces or clefts representing decalcified enamel, cementoid globules, and pulp tissue were evident [Figure 6]c and [Figure 6]d. Based on clinical, radiographic, and histopathologic features, the case was diagnosed as AFO or CO.
Figure 5: Gross tissue specimen

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Figure 6: Photomicrographs of the decalcified tissue sections showing odontogenic epithelium (blue arrow) with mineralized tissue (yellow arrow) (a, H and E stain, ×20); dental papilla like primitive ectomesenchyme (b, H and E stain, ×10); dentin like material (yellow arrow) and pulp tissue (red arrow) (c, H and E stain, ×10); and enamel matrix (yellow arrow), enamel space (blue arrow), and cementoid globules (red arrow) (d, H and E stain, ×4)

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   Discussion Top


The origin of AFO is widely debated. The WHO 2005 had classified AFO and CO into distinct entities.[4] As per previously published literature, AF existed as two types – neoplastic type, if it does not mature and remains as AF, and hamartous type, which undergoes maturation to form CO.[4],[5] The theory of the continuum concept of maturation postulated by Cahn and Blum in 1952 suggested that ameloblastic fibroma, AFO, AFD, and CO represent evolutionary stages of the same lesion, with AF being least differenced lesion and odontoma being fully differentiated lesion.[4],[6] The WHO in 2017 described AFO to be representing a developing CO and the decision was made to group them under odontoma.[3]

AFO accounts for 1%–3% of all tumors of odontogenic origin. It has a male predilection and often reported in persons younger than 20 years.[5] Buchner et al. showed a mean age of 9.6 years with a sex ratio of male to female = 1.85:1,[7] while Chrcanovic and Gomez gave a mean age of 9 ± 5.4 years with a sex ratio of male to female = 1.3:1.[8] They have also mentioned about central variant and extremely rare peripheral variants of AFO. Mandibular lesions were more often than the maxillary. However, the present case was in a girl younger to the mean age and the lesion was in the maxillary posterior region. This condition is often accompanied with an unerupted tooth. Tumors associated with primary dentition are mainly seen in the anterior region and those with secondary dentition are seen in the posterior region.[5]

Clinically, AFO or CO appears as an asymptomatic, slow-growing lesion often seen with unerupted teeth and common complaints include swelling and delay in tooth eruption. The clinical picture of AFO correlates well with the present case. These lesions can be solitary as in the present case or multiple. Botelho et al. have listed multiple COs.[9] These lesions may reach enormous size causing complications such as cortical expansion, facial disfigurement, difficulty in feeding, difficulty in breathing due to nasal obstruction, destruction of the maxillary sinus, and destruction of floor of the orbit causing proptosis. Some may result in the perforation of the buccal cortex and present as peripheral lesions which may mimic gingival lesions.[10] AFO may be misidentified as enamel pearl if it is in close association with a tooth, however, the latter is often associated with periodontitis.[11]

Radiographically, they appear as unilocular or multilocular radiolucency with radio-opaque foci and sclerotic margins. Some cases are diagnosed incidentally during routine radiographic examination in the initial stages. Resorption of the bone or tooth roots, expansion of cortical plates, impacted tooth, or misplaced teeth may be associated features.[6] The radiographic differential diagnosis of AFO should include other calcifying odontogenic lesions such as AFD, compound and CO, odontoameloblastoma, Gorlin's cyst, adenomatoid odontogenic tumor, Pindborg's tumor, and dentinogenic ghost cell tumor.[3],[5],[12] Among odontomas, complex odontoma shows disorderly arranged hard tissues such as dentin, enamel, and cementum as densely packed, a homogeneous calcified mass on CT scans, while compound odontoma shows orderly hard tissue arrangement each reminiscent of a tooth.[5],[13]

Histopathologically, AFO comprises odontogenic epithelial islands or nests scattered in dental papilla-like stroma with the presence of mineralized tissue like enamel matrix and dentin or osteodentin. The volume of epithelial islands and ectomesenchyme diminishes slowly and more mineralized tissue formation is seen as the lesion matures which was evident in this case.[5] Histopathological differential diagnosis of AFO includes ameloblastic fibroma which can be excluded by the absence of hard tissue formation. Some of the differential diagnoses are summarized in [Table 1].[2],[6],[12]
Table 1: Differentialdiagnosisofameloblasticfibro-odontoma[2],[6],[12]

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Intense cellularity, rich stellate or spindle-shaped atypical fibroblasts, and mitosis in ectomesenchyme represent an aggressive behavior of the lesion.[5] Sekine et al. studied the cell kinetics of AFO using bromhexine and proliferating cell nuclear antigen and revealed that the ectomesenchyme was more actively proliferating than the odontogenic epithelium.[14] However, no such aggressive finding was found in the present case.

Ultrastructurally, tubular dentin, dentinoid, and cementoid-like tissue with Sharpey's fiber-like structures have been described by some authors.[5] Reich et al. observed that the epithelial islands of AFO resembled the developing odontogenic epithelium, while odontoblasts differentiation from ectomesenchyme was not clear explaining the osteodentin or dentinoid material.[15]

Complete surgical enucleation including extraction of the impacted teeth is the suggested treatment. Tumor resection is based on the histological diagnosis.[13] The preservation of the unerupted tooth with successful eruption into the occlusal plane at a later stage is also advocated.[16] Recurrence is usually not common in AFO unless there is an inadequate surgical removal or after the preservation of the unerupted tooth.[17] If preservation of the unerupted tooth is done, monitoring of patients is essential till impacted tooth erupts and to observe recurrence. Our patient is kept under observation. Larger destructive tumors warrant partial maxillectomy or mandibulectomy. Malignant transformation to ameloblastic fibrosarcoma or ameloblastic fibro-odontosarcoma is rarely seen and seems to occur in older age. Nevertheless, aggressive lesions warrant a more radical surgical procedure.[18] Marked cellularity, dysplastic fibroblasts, and high mitotic figures in ectomesenchyme warrant more extensive procedure.[4],[5],[6]


   Conclusion Top


AFO is usually a central lesion but may sometimes present as a peripheral lesion which causes difficulty in diagnosis. Confirmation by histopathologic examination is needed for appropriate treatment.

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.

Acknowledgement

We would like to thank Dr. Madhushankari and Dr. Ashwini, Department of Oral Pathology, College of Dental sciences, Davangere, Karnataka, for their support.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
Hooker SP. Ameloblastic odontoma: An analysis of 26 cases. Oral Surg Oral Med Oral Pathol 1967;24:375-6.  Back to cited text no. 1
    
2.
Soluk-Tekkeşin M, Wright JM. The World Health Organization Classification of Odontogenic Lesions: A Summary of the Changes of the 2017 (4th) Edition. Turk Patoloji Derg 2018;34. doi: 10.5146/tjpath.2017.01410. PMID: 28984343.  Back to cited text no. 2
    
3.
Wright JM, Vered M. Update from the 4th edition of the World Health Organization classification of head and neck tumours: Odontogenic and maxillofacial bone tumors. Head Neck Pathol 2017;11:68-77.  Back to cited text no. 3
    
4.
Slootweg PJ. An analysis of the interrelationship of the mixed odontogenic tumors--ameloblastic fibroma, ameloblastic fibro-odontoma, and the odontomas. Oral Surg Oral Med Oral Pathol 1981;51:266-76.  Back to cited text no. 4
    
5.
Reichart R, Philipsen H, Gelderblom H, Stratmann U. Ameloblastic fibro-odontoma-report of two cases with ultrastructural study of tumour dental hard structures. Oral Oncol 2004;40:8-12.  Back to cited text no. 5
    
6.
Cohen DM, Bhattacharyya I. Ameloblastic fibroma, ameloblastic fibro-odontoma, and odontoma. Oral Maxillofac Surg Clin North Am 2004;16:375-84.  Back to cited text no. 6
    
7.
Buchner A, Kaffe I, Vered M. Clinical and radiological profile of ameloblastic fibro-odontoma: An update on an uncommon odontogenic tumor based on a critical analysis of 114 cases. Head Neck Pathol 2013;7:54-63.  Back to cited text no. 7
    
8.
Chrcanovic BR, Gomez RS. Ameloblastic fibrodentinoma and ameloblastic fibro-odontoma: An updated systematic review of cases reported in the literature. J Oral Maxillofac Surg 2017;75:1425-37.  Back to cited text no. 8
    
9.
Botelho J, Machado V, Gomes JC, Borrecho G, Maia P, Mendes JJ, et al. Multiple complex odontomas of the mandible: A rare case report and literature review. Contemp Clin Dent 2019;10:161-5.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Hegde V, Hemavathy S. A massive ameloblastic fibro-odontoma of the maxilla. Indian J Dent Res 2008;19:162-4.  Back to cited text no. 10
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11.
Lee E, Shin J, Kim S, Jeong T. Ameloblastic fibro-odontoma misidentified as an enamel pearl. J Dent Child (Chic) 2020;87:44-7.  Back to cited text no. 11
    
12.
Yonetsu K, Nakamura T. CT of calcifying jaw bone diseases. AJR Am J Roentgenol 2001;177:937-43.  Back to cited text no. 12
    
13.
Cossiez M, Pin DD. A rare case of maxillary ameloblastic fibro-odontoma and a review of the literature. J Oral Med Oral Surg 2020;26:17.  Back to cited text no. 13
    
14.
Sekine J, Kitamura A, Ueno K, Sano K, Inokuchi T, Takahashi H, et al. Cell kinetics in mandibular ameloblastic fibro-odontoma evaluated by bromodeoxyuridine and proliferating cell nuclear antigen immunohistochemistry: Case report. Br J Oral Maxillofac Surg 1996;34:450-3.  Back to cited text no. 14
    
15.
Reich R, Reichart PA, Ostertag H. Ameloblastic fibroodontoma. Report of a case, with ultrastructural study. J Maxillofac Surg 1984;12:230-4.  Back to cited text no. 15
    
16.
Okui T, Ibaragi S, Shimo T, Takabatake K, Fujita M, Hassan NM, et al. Ameloblastic fibro-odontoma in a 9-year-old boy. Stomatological Dis Sci 2018;2:7.  Back to cited text no. 16
    
17.
Furst I, Pharoah M, Phillips J. Recurrence of an ameloblastic fibro-odontoma in a 9-year-old boy. J Oral Maxillofac Surg 1999;57:620-3.  Back to cited text no. 17
    
18.
Howell RM, Burkes EJ Jr. Malignant transformation of ameloblastic fibro-odontoma to ameloblastic fibrosarcoma. Oral Surg Oral Med Oral Pathol 1977;43:391-401.  Back to cited text no. 18
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1]



 

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