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| CASE REPORT |
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| Year : 2022 | Volume
: 49
| Issue : 3 | Page : 352-355 |
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Ameloblastoma, a tumor with an infamous notoriety for recurrence
Miheer Milind Jagtap1, Samarth Shukla1, Dhanushree Nair2
1 Department of Pathology, Jawaharlal Nehru Medical College, DMIMS (Deemed to be University), Wardha, Maharashtra, India
2 Gastroenterology, Jawaharlal Nehru Medical College, DMIMS (Deemed to be University), Wardha, Maharashtra, India
| Date of Submission | 08-Jun-2022 |
| Date of Acceptance | 09-Aug-2022 |
| Date of Web Publication | 27-Dec-2022 |
Correspondence Address:
Dr. Miheer Milind Jagtap
Department of Pathology, Jawaharlal Nehru Medical College, DMIMS (Deemed to be University), Wardha, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jss.jss_115_22
Ameloblastoma is a locally invasive epithelial tumor of odontogenic origin comprising 1% or less of the cystic lesions and tumors arising in the jaws. It is a lesion most commonly seen in the molar region of the mandibular ramus. Ameloblastomas can be both benign and malignant and this can be differentiated by certain unique morphological features. In the older histology nomenclature, the term “adamantinoma” was used instead of ameloblastoma. The chances of recurrence can be high or low depending upon the surgical management. Curettages are associated with high recurrence rates while wide local excision tends to reduce recurrences.
Keywords: Adamantinoma, carcinoma, enamel, odontogenic, soap bubble appearance, treatment
How to cite this article:
Jagtap MM, Shukla S, Nair D. Ameloblastoma, a tumor with an infamous notoriety for recurrence. J Sci Soc 2022;49:352-5 |
| Introduction | |  |
Ameloblastoma is an odontogenic epithelial neoplasm. The origin of the word ameloblastoma can be found in the early English literature; “amel” means enamel and the Greek word “blastos” means germ. Postulated to be arising from the enamel organ, remnants of odontogenic cyst and the remains of Serres, ameloblastomas are locally aggressive tumors with a high propensity for recurrence.[1]
| Case Report | | |
A 51-year-old female reported having visible swelling on the right side of her face since last 1 year with pain while eating for 2 months. Examination showed an ill-defined solitary swelling which was initially 2 cm × 2 cm × 1 cm in size and gradually progressed to the present size of 5 cm × 4.5 cm × 4 cm. No history of either trauma, toothache or discharge was present. The lesion was identified on radiological examination and surgically managed by hemi-mandibulectomy. Reconstruction was done simultaneously using iliac crest bone.
| Discussion | | |
Ameloblastomas predominantly originate as benign tumors but rarely, they can evolve into or be associated with malignant transformation. The malignant counterpart is termed as “malignant ameloblastoma” or “ameloblastic carcinoma”[1] Previously known as “adamantinoma,” which was proposed by Malassez in 1885, this tumour's nomenclature has undergone various amendments.[2],[3]
The nomenclature of this tumor has undergone the following changes in the recent years:
- The name “solid/multicystic ameloblastoma” was changed to “conventional ameloblastoma” in the WHO 2017 classification, 4th edition
- The WHO 2017 classification, 4th edition recommended to use the term “desmoplastic ameloblastoma” as a variant of the conventional ameloblastoma
- Metastasizing ameloblastoma was a term used in the WHO 2005 classification. It was removed from the classification of malignant odontogenic tumors and was reclassified as a benign odontogenic entity in the WHO 2017 classification.[4]
Considering the epidemiological aspects, this tumor is the most common odontogenic neoplasm equally affecting both the sexes from second to the seventh decade of life. The conventional variant aka intraosseous gnathic ameloblastoma predominantly affects the mandible and a small portion of the cases present with a maxillary presentation. Extraosseous ameloblastomas usually involve the gingiva and the retromolar area while other sites include the sinonasal tract, middle ear, temporal bone and the infratemporal fossa.[5]
The cells termed as ameloblasts are derived from the ectoderm and are seen only in the tooth development phase. They are involved in the deposition of enamel and become functionally potent only after the formation of dentin. Ameloblasts eventually are incorporated into the enamel epithelium and undergo programmed cell death by apoptosis after tooth eruption.
It has been documented that, genetic mutations interfere with the normal functioning of the mitogen activated protein kinase pathway and drive uncontrolled cellular proliferation.[6]
The diagnosis of ameloblastoma requires a three-pronged approach: Clinical, radiological and histopathological correlation. A definitive diagnosis of ameloblastoma is obtained by biopsy histological examination which is a gold standard.
Clinically, ameloblastomas are asymptomatic and are discovered incidentally on radiological examination. They are usually slow growing causing painless expansion of the jaw which causes malocclusion and loosening of teeth. Pain and hemorrhage can be present in the event of an infection. Patients with ameloblastomas usually present with hypercalcemia due to increased levels of parathyroid hormone related protein and excessive bone demineralization. Radiologically, ameloblastomas are characterized by soap bubble appearance and may appear unilocular or multilocular depending on the number of cystic cavities. They appear as radiographically dark (radiolucent) lesions involving the maxilla, mandible.
Clinically, ameloblastomas could be associated with nevoid basal cell carcinoma syndrome (Gorlin syndrome).[7] Grossly, ameloblastomas are characterized by presence of viscous mucoid fluid and a combination of solid and cystic spaces. Occasionally, ameloblastomas are associated with an impacted tooth and bony extension may be present [Figure 1]. | Figure 1: Gross photograph of ameloblastoma with a solid cystic appearance. The cystic component shows the presence of semisolid and viscous hemorrhagic material
Click here to view |
Histologically, ameloblastoma is classified into 6 types: follicular, plexiform, acanthomatous, granular cell, basal cell/basaloid, and desmoplastic. Microscopically, it shows islands and sheets of cells arranged in a basaloid or a follicular pattern. The outer layer shows tall columnar cells arranged in a palisaded pattern while the inner layer shows “stellate reticulum.” “Vickers Gorlin change” is a phenomenon characterised by the cells showing reverse polarisation away from the basement membrane [Figure 2], [Figure 3], [Figure 4], [Figure 5]. On immunohistochemistry, CD56, calretinin, BRAF V600E, beta catenin, FOXP1 and cytokeratin. On electron microscopy, tonofilaments, complex desmosomes, and lysosomal aggregates are seen.[8] | Figure 2: Section stained with routine hematoxylin and eosin (H and E) stain, low-power view (×10) shows basaloid arrangement of cells along with adjacent stroma. Two types of cell population are appreciated
Click here to view |
 | Figure 3: Section stained with hematoxylin and eosin (H and E) stain, low power view (10x) shows cells arranged in a basaloid pattern with the cell nests showing hyperchromatic tumour cells arranged in a palidaded pattern. Cells with stellate reticulum are also seen in the center
Click here to view |
 | Figure 4: Section stained with hematoxylin and eosin (H and E) stain, high power view (40x) shows a single tumour nest. There are hyperchromatic tumour cells arranged in a palisaded pattern in the periphery. The central part shows stellate reticulum like cells. Scant intervening fibrous stroma is seen with occassional chronic inflammatory cells
Click here to view |
 | Figure 5: Section stained with routine hematoxylin and eosin (H and E) stain, high-power view (×40) shows a small nest of tumor cells with 2 cell populations: Cells in the periphery showing palisading arrangement and stellate reticulum cells in the center
Click here to view |
It is of utmost importance that a benign ameloblastoma is distinguished from an ameloblastic carcinoma. These 2 disease entities have certain overlapping features like stellate reticulum cells, palisading in the periphery and reverse polarization. Ameloblastic carcinoma can be identified by the following morphological features: high mitotic activity, cellular atypia, perineural and vascular invasion, and nuclear pleomorphism.
The other differential diagnosis of ameloblastoma includes ameloblastic fibroma which is a benign mixed (epithelial–mesenchymal) tumor with nests of cuboidal to columnar cells with stellate reticulum and “prominent” basement membrane. Another differential is basal cell carcinoma and it can be identified by the presence of a desmoplastic stroma, prior history of skin cancer and mitotic activity. Other entities need to be ruled out like odontogenic keratocyst, odontogenic myxoma, and central giant-cell granuloma.[9]
Ameloblastomas treated with only curettage have a high tendency for recurrence while marginal resection with 1 cm margins is associated with reduced recurrence rates. Histological variants of ameloblastoma do not affect the prognosis. Ameloblastomas arising from the maxilla show high recurrence rates. Prognostic factors associated with high recurrence rate are tumors arising from the maxilla, BRAF V600E mutation, and tumors treated with simple curettage.[10]
| Conclusion | | |
Considering this entity's notoriety for recurrence, a multidisciplinary approach becomes necessary to achieve the best outcome. Major surgeries in the facial area cause deforming esthetic changes due to which the role of oral maxillofacial and plastic surgeons in facial reconstruction becomes necessary. Similarly, expert speech language pathologists and voice therapists are vital for the voice management, odynophagia, and dysphagia issues arising after excision. Thus, an open line of communication between all the members has to be maintained so that best outcome is achieved through a collective interprofessional approach.
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.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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| 8. | Nakamura N, Mitsuyasu T, Higuchi Y, Sandra F, Ohishi M. Growth characteristics of ameloblastoma involving the inferior alveolar nerve: A clinical and histopathologic study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:557-62. |
| 9. | Chen Y, Wang JM, Li TJ. Ameloblastic fibroma: A review of published studies with special reference to its nature and biological behavior. Oral Oncol 2007;43:960-9. |
| 10. | Hendra FN, Natsir Kalla DS, Van Cann EM, de Vet HCW, Helder MN, Forouzanfar T. Radical vs. conservative treatment of intraosseous ameloblastoma: Systematic review and meta-analysis. Oral Dis 2019;25:1683-96. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
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