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Year : 2020  |  Volume : 11  |  Issue : 4  |  Page : 216-219

Looking through the keyhole: A case report of odontome with keyhole pattern in histopathology

Department of Oral and Maxillofacial Pathology, SRM Dental College, Chennai, Tamil Nadu, India

Date of Submission28-Oct-2020
Date of Acceptance17-Nov-2020
Date of Web Publication05-Feb-2021

Correspondence Address:
Dr. Lekshmy Jayan
Department of Oral and Maxillofacial Pathology, SRM Dental College, Ramapuram, Chennai, Tamil Nadu
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DOI: 10.4103/srmjrds.srmjrds_110_20

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Odontome is the most frequent mixed type of odontogenic tumor comprising 22% of all odontogenic tumors. They are divided into two types namely, compound and complex types on the basis of the differentiation and organization of the dental tissues. The diagnosis of odontome relies on the clinical and radiographic evaluation of the lesion. This article presents an unusual case of compound composite odontome with prominent keyhole pattern in maxilla of a 23-year-old male patient.

Keywords: Compound odontomes, hamartomas, histopathological examination, keyhole pattern, odontomes

How to cite this article:
Mohan VK, Gunasekaran S, Aruna Jeslyn V S, Nabeela A, Barath B, Venkatesalu B, Jayan L. Looking through the keyhole: A case report of odontome with keyhole pattern in histopathology. SRM J Res Dent Sci 2020;11:216-9

How to cite this URL:
Mohan VK, Gunasekaran S, Aruna Jeslyn V S, Nabeela A, Barath B, Venkatesalu B, Jayan L. Looking through the keyhole: A case report of odontome with keyhole pattern in histopathology. SRM J Res Dent Sci [serial online] 2020 [cited 2021 Mar 5];11:216-9. Available from:

  Introduction Top

The term odontome represents a tumor which is of odontogenic origin, the exact origin of which is still greatly controversial. Many authors consider this entity to be a true mixed odontogenic tumor; however, few authors challenge this and suggest this entity to be hamartomas rather than a true neoplasm. Odontomes have a prevalence of around 20% of all odontogenic tumors.[1] Odontome can be of two types; it can either present with the components of the tooth arranged in the same differentiated manner as in a tooth but having a smaller size than actual tooth (Compound composite odontome) or it can be haphazardly arranged (Complex composite odontome).[1],[2],[3]

The mixed nature of the tumor is produced by the presence of epithelial mesenchymal interactions, which normally mediate the differentiation of enamel, dentin, pulp, and cementum in odontogenesis. In odontome, some unknown etiological triggers induce abnormal epithelial mesenchymal interactions which produce this lesion, owing to the defective morphodifferentiation. Although many etiological factors are proposed, it is all substantial and still no definitive etiological agent is devised.[4]

In this article, we present a case of compound composite odontome revealing keyhole pattern on histopathological examination in a 23-year-old male.

  Case Report Top

A 23-year-old male patient reported to the department with a chief complaint of discoloration of front teeth for the past 3 years. There is no history of pain and swelling in the mentioned region. Discoloration of 11 and 21 was noticed, and on eliciting the clinical history, the patient reported a history of trauma 13 years back, with the discoloration presenting for the past 3 years. On systemic examination, all vital signs were within normal limits. On extraoral examination, no abnormalities were detected. On examination of hard tissues in the oral cavity, tooth discoloration was present in relation to 11 and 21.

On radiographic evaluation, multiple radiopaque structures with variation in the radiographic density resembling tooth structures were evident in relation to the periapical region of 11, 21, and 22, which supported the diagnosis of odontome [Figure 1].
Figure 1: Computed tomography showing odontome in the apical region of 21 and 22

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The odontomes were removed by surgical enucleation, and the specimen was sent for histopathological examination [Figure 2],[Figure 3],[Figure 4]. Histopathological examination of the specimen revealed few teeth-like structures exhibiting peripheral enamel-like tissue showing keyhole pattern followed by eosinophilic mature dentin and predentin areas with the innermost pulpal tissue. Surrounding stroma shows dense collagen fibers which appears condensed in few areas resembling dental follicles, fibroblasts, blood vessels, and extravasated red blood cells and globular to irregular structures with peripheral hematoxyphilic cementum-like tissue and centrally placed eosinophilic dentin-like areas. There is also evidence of bone in the periphery. The histopathology is suggestive of compound composite odontome [Figure 5] and [Figure 6].
Figure 2: Intraoral view showing small tooth-like structures

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Figure 3: Postoperative surgical site after removal of the odontome

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Figure 4: Gross specimen showing four odontomes

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Figure 5: Histopathological examination of the specimen at 4X view showing tooth-like structure

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Figure 6: Histopathological examination of the specimen at 20X view showing keyhole pattern

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  Discussion Top

Pierre Paul Broca first coined the term odontome in 1867 to represent “tumors formed by the overgrowth of transitory or complete dental tissues.”[5] It has a slight predilection for males in their second to third decade of life. The different types of odontomes have differing predilection for their occurrence, with compound composite odontome being more common in the anterior region of the jaw and complex odontomes arising more commonly in the posterior regions of the jaw.[6],[7] Our case followed these epidemiological parameters of the condition as the lesion was seen in a 23-year-old male in his maxillary anterior tooth region. The patient gave a history of trauma to the affected site 13 years back; this may be considered as the etiological trigger in this particular case. Again, there was no alteration evident in the neighboring tooth probably because the lesion was seen well below the apical portion of the involved teeth.

In 2017, in their fourth edition, the World Health Organization removed the concept of ameloblastic fibro-odontoma and fibrodentinoma and suggested that these entities represent maturing phase of odontome and are not separate entities. They also emphasized that the current classification of odontome does not warrant any significance as they are managed by the same manner.[8]

The various etiological factors implicated in odontome are elaborated in [Table 1].[8],[9],[11]
Table 1: Etiological factors for odontome

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Various classification systems are devised for odontome, which are compiled in [Table 2].[6],[7],[8],[9],[10]
Table 2: Classification of odontome

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Clinically, majority of the cases are asymptomatic and are diagnosed when radiographic evaluation is done for some other complaints. In few cases, especially those with complex odontome, there may be a clinically evident expansive lesion. The diagnosis of this entity relies on the clinical history of a missing tooth and radiographic visualization of denticles or a conglomerate mass of mineralized tissue with a thin radiolucent rim resembling the follicular space surrounding unerupted tooth. Radiographic examination of odontome will show three stages based on the extent of mineralization: in the initial stage, the odontome is unmineralized and appears radiolucent; in the second stage, it is partially mineralized and will show radiopaque flecks; and in the final matured stage, the specimen will be fully mineralized appearing radiopaque.[7]

Treatment of choice for odontome is surgical excision with histopathological examination of the resected specimen. The histopathological differential diagnoses for odontome are ameloblastic fibro-odontoma and odontoameloblastoma, which resemble this lesion on radiographic examination.[2]

Odontome is associated with numerous possible complications. If the odontome has erupted, it can entrap food materials and be affected by caries which may even progress to periapical infection. Sometimes, this can develop a dentigerous cyst in relation to the odontome. The lesion can block the path of eruption of normal tooth or may cause displacement of overlying tooth. Neoplasms such as ameloblastoma or malignant carcinomas are reported to have arisen from this lesion.[1]

  Conclusion Top

Odontome is the most common odontogenic tumor derived from both the epithelial and mesenchymal components of the tooth-forming apparatus. Diagnosis of the odontome relies on the clinical and radiographic examination and is merely supplemented by histopathology. It is commonly identified only when a radiograph is taken for some other purpose or rarely when clinical expansion is evident. Once treatment is done, it has good prognosis. Even though this entity is described since the 1960s, an understanding of how this lesion develops is still a mystery. Studies to reveal the underlying molecular mechanisms may help in unraveling the mystery of its origin.

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.

  References Top

Santhosh BS, Anuradha V, Dayanand MC. Erupting complex odontoma: Coronal to impacted second molar associated with dentigerous cyst. J Oral Health Comm Dent 2011;5:100-2.  Back to cited text no. 1
Rana V, Srivastava N, Kaushik N, Sharma V, Panthri P, Niranjan MM. Compound composite odontome: A case report. Int J Clin Pediatr Dent 2019;12: 64-7.  Back to cited text no. 2
Vaid S, Ram R, Bhardwaj VK, Chandel M, Jhingta P, Negi N, et al. Multiple compound odontomas in mandible: A rarity. Contemp Clin Dent 2012;3:341-3.  Back to cited text no. 3
[PUBMED]  [Full text]  
John JB, John RR, Elango PI. Compound odontoma associated with maxillary primary tooth – A case report. J Indian Acad Dent Spec 2010;1:49-51.  Back to cited text no. 4
Barba LT, Campos DM, Nevárez Rascón MM, Ríos Barrera VA, Rascón AN. Descriptive aspects of odontoma: Literature review. Revista Odontológica Mexicana 2016;20:265-9.  Back to cited text no. 5
Barnes L, Eveson JW, Sidransky D, Reichart P, editors. Pathology and genetics of head and neck tumours. IARC; 2005;9:284-327.  Back to cited text no. 6
Philipsen HP, Reichart PA. Classification of odontogenic tumours. A historical review. J Oral Pathol Med 2006;35:525-9.  Back to cited text no. 7
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. 8
Prabhu N, Issrani R, Patil S, Srinivasan A, Alam MK. Odontoma - An unfolding enigma. J Int Oral Health 2019;11:334-9.  Back to cited text no. 9
  [Full text]  
Buchner A, Merrell PW, Carpenter WM. Relative frequency of central odontogenic tumors: A study of 1,088 cases from Northern California and comparison to studies from other parts of the world. J Oral Maxillofac Surg 2006;64:1343-52.  Back to cited text no. 10
Gervasoni C, Tronchet A, Spotti S, Valsecchi S, Palazzolo V, Riccio S, et al. Odontomas: Review of the literature and case reports. J Biol Regul Homeost Agents 2017;31:119-25.  Back to cited text no. 11


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

  [Table 1], [Table 2]


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