|Year : 2022 | Volume
| Issue : 3 | Page : 336-344
Odontogenic tumors: A histopathological overview
Sumedha P Shinde1, Arvind J Vatkar2
1 Department of Pathology, Dr. D Y Patil Medical College and Hospital, Navi Mumbai, Maharashtra, India
2 Queen's Medical Centre, Lenton, Nottingham, United Kingdom
|Date of Submission||02-Apr-2022|
|Date of Acceptance||29-Jun-2022|
|Date of Web Publication||29-Sep-2022|
Sumedha P Shinde
Department of Pathology, Dr. D Y Patil Medical College and Hospital, Sector 7, Nerul, Navi Mumbai 400706, Maharashtra
Source of Support: None, Conflict of Interest: None
Introduction: Odontogenic tumors (OTs) are rare and account for around 1% of jaw lesions including tumor and tumor-like lesions. OTs are a diverse category of lesions, displaying different inductive interactions. Although some are hamartomas, others are benign and malignant neoplasms with varying degrees of aggressiveness. Materials and Methods: We plan to review the histopathological aspects of OTs because of their diverse properties. At a tertiary medical and dental institute in Pune, India, we studied 28 cases of OTs over 2 years, from 2013 to 2015. Results: The most common forms of OTs were ameloblastoma (42.86%) and odontogenic keratocyst (21.15%). The highest number of OTs was found in the 21–30-year-old age group, with an even gender distribution. Conclusion: Ameloblastoma is the most common OT, accounting for roughly one-quarter of all jaw tumors. The majority of OTs occurs in young people aged 20–40 years. Fortunately, malignant OTs are extremely rare.
Keywords: Ameloblastoma, myxoma, odontogenic keratocyst, odontogenic tumors, odontoma
|How to cite this article:|
Shinde SP, Vatkar AJ. Odontogenic tumors: A histopathological overview. MGM J Med Sci 2022;9:336-44
| Introduction|| |
Odontogenic tumors (OTs) are lesions that arise from the various dental tissues from epithelial, ectomesenchyme, and/or mesenchymal elements. It is a complex set of lesions with a wide variety of histological and clinical symptoms, and the biological behavior of these lesions can range from hamartomatous or non-neoplastic cell proliferation to malignant tumors. The location (central vs. peripheral) and biological behaviors (benign vs. malignant) of OT can be used to classify them. Epithelial, mesenchymal, and mixed are the three types recognized by the World Health Organization (WHO). The histopathological study of OTs is necessary because of their varied behavior.
| Materials and methods|| |
From July 2013 to September 2015, the surgical histopathology data of the Dr. D Y Patil Medical College and Dental College and Hospital, Pimpri, Pune, India were reviewed retrospectively. A total of 26 OTs were compiled and examined. The investigator examined the hematoxylin and eosin-stained segments, and in each event, the diagnosis either was confirmed or amended by the WHO classification’s third edition. The frequency and distribution of age, sex, and primary site of the lesion were evaluated in comparison with research published in the journal before and after the 4th edition of WHO—Head and Neck Tumors-Odontogenic and Maxillofacial Bone Tumors categorization.
| Results|| |
In total, 28 cases were of OTs. All patients were analyzed based on their demographics, location of the tumor, age distribution, and x-ray appearances.
Types of OTs and their prevalence
The most prevalent OT was ameloblastoma, which accounted for 42.9% of all cases. Odontogenic keratocyst lesions, which accounted for 39.3% of the cases, came close behind. Finally, odontogenic myxoma and odontoma accounted for 14.3% and 3.6% of the cases, respectively.
OTs had a 1:1 sex ratio. However, in ameloblastoma and odontogenic keratocyst, there was a slight male preponderance. Despite the low overall population, females are more likely to develop odontogenic myxoma and odontome.
In their second and third decades of life, over 68% of patients developed OT. The majority of individuals with OT were between the ages of 21 and 30 years (10 patients). The age group of 31–40 years came in the second (nine patients). In the first and fifth decades of life, respectively, one case was diagnosed.
Location of OTs (mandible vs. maxilla)
The highest number of OTs was found in the mandible (89%). Ameloblastoma and odontogenic myxoma were found only in the mandible. The solitary odontome was discovered on the maxilla’s anterior side.
The x-ray results of ameloblastoma tumors varied slightly, although the majority of them appeared as multilocular radiolucency. Unilocular bone loss was seen in three cases. The x-ray results in odontogenic keratocysts varied little, although the majority of them exhibited multilocular radiolucency. The most common kind of odontogenic myxoma was multilocular radiolucency with lytic lesion and expansion. Radio-opaque mass was found in the odontome. Below are a few x-rays [Figure 1][Figure 2][Figure 3][Figure 4] of different types of OTs.
|Figure 1: Skiagram of ameloblastoma showing osteolytic lesion with sclerotic margins|
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|Figure 2: Skiagram of ameloblastoma showing osteolytic unilocular lesion with sclerotic margins|
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|Figure 3: Skiagram of keratocystic odontogenic tumor with well-circumscribed unilocular radiolucency with smooth radiopaque margin|
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|Figure 4: Skiagram of jaw showing odontome with radiolucent, well-circumscribed mineralized masses with focal areas of opacity, which represents early calcification of dentine and enamel|
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Histopathological details of OTs
There were two major histological patterns identified. Four (33.34%) of the 12 ameloblastoma cases had a follicular pattern, six (50%) had a plexiform pattern, and one (8.34%) had a mixed pattern. In one case, an acanthomatous variant was discovered (8.34%); the ameloblastic epithelium in the follicular pattern tumor was in the form of discrete islands. These islands were made up of palisading columnar cells on the periphery and a loose area in the center that resembled stellate reticulum. Only a few of the islands had cystic change. The epithelium was arranged in a network of anastomosing strands bound by a layer of columnar cells and a central loose stellate reticulum-like area in a plexiform pattern tumor. [Figure 5] and [Figure 6] show a photomicrographic view of follicular and plexiform ameloblastomas, respectively.
|Figure 5: Photomicrograph showing follicular ameloblastoma exhibiting tall columnar epithelial components in prominent follicular fashion. There are cystic spaces in the stellate reticulum (H&E, 10×)|
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|Figure 6: Photomicrograph showing plexiform ameloblastoma with areas of stellate cell stroma and islands of tall columnar epithelial cells (ameloblastic cells) in equal proportions (H&E, 10×)|
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One case displayed the acanthomatous pattern. A portion of the tumor was made up of epithelial islands composed of squamous cells, whereas another portion was an entire of ameloblast-like cells that resembled stellate reticulum. Keratin pearl formation was observed in some areas. The ameloblastomas were all benign.
The walls are thin and fragile. The epithelial lining is thin and uniform, with cuboidal or columnar basal cells. The surface layer of parakeratin is thin and has a corrugated appearance. Inflammatory cells are absent from the fibrous tissue capsule. [Figure 7] and [Figure 8] show a photomicrograph of odontogenic keratocyst at 10× and 40× magnification, respectively.
|Figure 7: Photomicrograph of keratocystic odontogenic tumor showing thickened orthokeratotic surface with uniformly thin epithelium without rete ridges. Subepithelial tissue shows thickened connective tissue (H&E, 10×)|
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|Figure 8: Photomicrograph of keratocystic odontogenic tumor showing thickened orthokeratotic surface with uniformly thin epithelium without rete ridges. Subepithelial tissue shows thickened connective tissue (H&E, 40×)|
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Myxoma has a minimal encapsulation. It extends through the bone into the soft tissues with no discernible margin. It is made up of rounded and angular cells that are embedded in a myxoid stroma. Atypical nuclei are possible. This tumor does not spread. The amount of collagen in a tumor varies. It is difficult to completely remove a tumor. Recurrence is common. [Figure 9] shows a photomicrograph of odontogenic myxoma.
|Figure 9: Photomicrograph showing myxoma. It shows a biphasic population consisting of stellate cells and fibroblasts in myxoid background (H&E, 10×)|
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Complex odontomes are made up of enamel, dentine, and cementum in their normal embryonic relationship, but they bear no resemblance to teeth. There may be traces of odontogenic epithelium present. Some odontomes contain ghost cells. Compound odontomes are made up of numerous denticles that are scattered throughout a fibrous tissue stroma.
Complex odontomes are represented in a more orderly pattern than dental tissues. [Figure 10] depicts a photomicrograph of the odontome at 40× magnification. [Table 1] summarizes the types of OTs, with their demographics, radiological findings, and age distribution.
|Figure 10: Photomicrograph of odontome comprises numerous denticles scattered throughout a stroma of fibrous tissue (H&E, 40×)|
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|Table 1: Demographics and x-ray characteristics and age distribution of odontogenic tumors|
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| Discussion|| |
In summary, ameloblastoma and odontogenic keratocyst were the most prevalent OTs in our analysis, accounting for around 2/3 of the cases. The majority of cases were found in the mandible. The majority of patients developed OTs in their second and third decades of life. The most common histologic patterns in ameloblastoma were follicular and plexiform. Although the gender ratio was equal, there were more males with ameloblastoma and odontogenic keratocyst.
Bhaskar classified jaw tumors into three types: odontogenic, nonodontogenic, and cystic. In 1992, the WHO proposed the second edition of its classification, which included three major divisions. With ameloblastoma, there were numerous changes. Some newly recognized OTs were added, and some lesions from the first edition were reclassified or merged into different subgroups. The fourth edition of the WHO Classification of Odontogenic Tumors, Cysts, and Related Lesions was published in 2017.
The age, gender, and location of odontogenic and nonodontogenic jaw tumors differ. Clinical, radiological, and histopathological correlations are used to make the diagnosis. Histopathological features aid in predicting the course of the lesion and planning therapy.
| Odontogenic tumors|| |
The frequency of different OTs as a percentage of all OTs gave the following results in [Table 2] when comparing studies by different authors. The relative prevalence of OTs was compared in numerous studies. The most common OT in this study was ameloblastoma, which accounted for 42.86% of all OTs.
|Table 2: Comparison of odontogenic tumors’ relative frequency in different studies|
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The most frequent OT is ameloblastoma. It is usually harmless. It may be malignant, meaning it is locally invasive or has distant metastasis. According to Regezi et al., the proportional prevalence of ameloblastoma among all OTs ranges from 11% in Americans to 80%–90% in Africans, according to Chidzonga et al.
There is a geographic diversity, according to several workers, with a maximal frequency of 50%–90% in Asian and African countries. The relative frequency of ameloblastoma among all OTs was 42.86% in this study. It is equivalent to the rates of other Asian laborers.
The majority of ameloblastoma instances occur in people between the ages of 20 and 50 years. Regezi et al. and Joshi et al. have all demonstrated this. Peak cases occurred between the third and fourth decades of life. The participants in this study ranged in age from 21 to 60 years old, with an average presenting age of 30 years. Seven (58.34%) of the 12 cases were in the age range of 21–40 years. These findings are consistent with those of previous investigations. There are seven cases in men (58.34%) and five cases in females (41.66%). There was a slight male preponderance. Reichart et al., Daley et al., and Luo and Li have reported a slight male preponderance. Ameloblastoma usually occurs in the mandible. Taylor et al. and Luo and Li reported an incidence of 60%–90% of ameloblastoma occurring in the mandible. Selvamani et al. showed 96.8% of cases were in mandible, whereas only 3.2% of cases were in the maxilla in the Indian population. In this study, all 12 cases were located in the mandible. The difference was due to less number of cases in this study compared with other studies.
According to a review by Reichart et al., follicular (33.9%) and plexiform variants (30.2%) of ameloblastoma constitute the most common histological variants. An acanthomatous type (11.37%) is also present. In this study, 33.34% showed a follicular pattern, the plexiform pattern was seen in 50% of cases, and 8.34% of cases showed a mixed pattern. Acanthomatous variants were found in 8.34% of cases.
The most frequent OT is a keratocystic OT. Osterne et al., Luo and Li, Sekerci et al., and others have estimated that keratocystic OTs account for 25%–40% of all OTs. Keratocystic OTs account for 39.29% of all OTs in this study, which is consistent with previous research. According to Sekerci et al and Chow, the highest age of incidence occurs in the second to fourth decade. The participants in this study ranged in age from 21 to 60 years, with 45.45% of cases in their fourth decade and 27.27% in their third. Its findings are in line with those of other researchers. According to Sekerci et al. and Chow, it has a male predominance. Males accounted for 54.54% of cases in this study, whereas females accounted for 45.45%, with a little male predominance. The same authors also mentioned that the keratogenic OT prefers the mandible above the maxilla. In this study, 81.81% of the cases were found in the mandible, whereas 18.18% were found in the maxilla, which was consistent with a previous research.
The epithelial lining is thin and homogeneous, with cuboidal or columnar basal cells, as indicated by microscopy. Parakeratin has a thin surface layer with a corrugated look. Inflammatory cells are absent from the fibrous tissue capsule. All histology results were compared with those of Sekerci et al. and Chow.
Odontogenic myxoma is a rare type of tumor. Myxoma, the most common of all OTs, affects 3% of Americans and 17% of Mexicans. In this investigation, four cases of myxoma were found, accounting for 14.28% of all OTs.
According to Daley et al., Taylor et al., Luo and Li, myxoma can affect people from the age of 17 months–65 years old, with a mean age of 20–30 years. Etemad et al. in this study found that 75% of the cases were between the ages of 21 and 30 years. Its findings are in line with those of other researchers. According to Etemad et al., there is a female predominance. This study found that 75% of instances were in girls and 25% in males, which is consistent with a previous research. According to Etemad et al., it prefers the mandible above the maxilla. All of the cases in this investigation were found in the mandible.
Histologically, myxoma shows little encapsulation. It extends through the bone into the soft tissues without any well-defined margin. It comprises rounded and angular cells lying in the mucoid stroma. Atypical nuclei may be present. This tumor does not metastasize. The amount of collagen in the tumor is variable. These findings are consistent with studies by others.
According to Amado et al., it is a benign OT with a modest development rate. Enamel, dentine, cementum, and pulpal tissue make up this structure. According to Amado et al., the age range of occurrence is 6–42 years, with a mean age of 29.3 years. According to Amado et al., there is a preference for the maxilla and a female predominance. According to Sarojini et al., Nelson and Thompson, Serra-Serra et al., and Singh et al., they usually occur in the first and second decades of life, with an equal sex distribution. Singh et al. reported that it is present in the first three decades of life, with a female predominance. A single example of compound odontome in a 9-year-old female patient is presented in this study. It was found in the region of the front maxilla. Its findings are in line with those of other researchers. It consists of many denticles dispersed across a stroma of fibrous tissue under the microscope. These findings are in line with those of other researchers.
| Conclusions|| |
- Every tumor must be correlated with clinical and radiological findings. Only a histological examination is not enough to provide a correct diagnosis.
- Ameloblastoma is the most common OT, accounting for 23.07% of jaw cancers and 42.86% of all OTs in the study.
- Malignant OTs are extremely rare. There is not a single case on this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
The approval from the Institutional Ethics Board of Dr. D Y Patil Medical College, and Dental College and Hospital, Pimpri, Pune, India, was taken as part of the postgraduate thesis protocol ethics approval for MD Pathology for the primary author on September 10, 2013.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]
[Table 1], [Table 2]