Mixed odontogenic tumors: A review of the clinicopathological and molecular features and changes in the WHO classification

Abstract

BACKGROUND Ameloblastic fibromas and ameloblastic fibrosarcomas are rare odontogenic tumors, and controversy exists in the classification of cases presenting hard-tissue production: Ameloblastic fibrodentinoma (AFD) and ameloblastic fibro-odontoma (AFO). These cases are currently considered “developing odontomas” (hamartomatous lesions). AIM To analyze the clinicopathologic features of these lesions and discuss the changes in the 2017 World Health Organization classification. METHODS An electronic literature search was performed in the PubMed/MEDLINE database. An electronic search of the English language literature was performed and last updated in September 2020 in the PubMed/MEDLINE database using the following terms: “ameloblastic fibroma”, “ameloblastic fibrodentinoma”, “ameloblastic fibro-odontoma”, “ameloblastic sarcoma”, “ameloblastic fibrosarcoma”, “ameloblastic fibrodentinosarcoma”, “ameloblastic fibroodontosarcoma” and “odontogenic carcinosarcoma”. The inclusion criteria were odontogenic tumor series, case reports and systematic reviews that provided sufficient clinical, radiological and microscopic documentation to confirm the diagnosis. RESULTS The database search strategy resulted in 947 papers. Articles focusing on other topics, articles that were not in English, duplicate articles, and articles without fulfilling the inclusion criteria were excluded. Finally, 96 publications were included in this review to describe and discuss the main features of the searched entities. Several aspects of AFO and AFD, such as biological behavior, age of occurrence, amount of hard tissue, and potential for malignant transformation into odontogenic sarcomas, support the neoplastic nature in most of the reported cases. Considering the clinical, radiographic, histopathological and molecular characteristics of odontogenic lesions with hard tissue production, we suggest that these types of lesions should continue to be recognized as odontogenic tumors by maintaining the classically used terms. CONCLUSION This recommendation will be relevant for future clinical, microscopic, and molecular studies to better understand the biology of these interesting odontogenic tumors.

Mystery Behind a Broken, Discolored Right Maxillary Central Incisor: A Case Report

“…Oliveira et al stated that compound odontoma can occur in calcifying odontogenic cyst resembling a tooth germ [ 15 ]. Odontomas are odontogenic tumors with less aggressive behavior [ 16 ]. Odontoma rarely erupts in the oral cavity and leads to impaction of underlying tooth [ 17 ].…”

Ameloblastic Fibrodentinoma and Ameloblastic Fibro-Odontoma: A Developing Odontoma or a Distinct Neoplasm?

“…Few studies have investigated the genetic/molecular profile of these tumors. 4 Reports of the presence of BRameloblastic fibroma p.V600E mutations in ameloblastic fibro-odontoma/ameloblastic fibrodentinoma, as observed in ameloblastic fibroma but different from odontoma, support the arguments that some of these tumors are indeed neoplastic, particularly those exhibiting locally aggressive behavior, large size, and recurrence. 7 The loss of heterozygosity of tumor suppressor genes has also been detected in ameloblastic fibroma and ameloblastic fibro-odontoma.…”

“…Previously, if dentin was present, the tumor was called ameloblastic fibrodentinoma; if dentin and enamel were observed, the tumor was called ameloblastic fibro-odontoma. 2,4 Ameloblastic fibro-odontoma and ameloblastic fibrodentinoma are rare tumors (accounting for 1%-3% of all odontogenic tumors) and affect people in the first and second decades of life. There is a male predilection and tumor size ranges from 3.0 to 14.0 cm.…”

“…There is a male predilection and tumor size ranges from 3.0 to 14.0 cm. 3,4,6 These tumors commonly occur in the posterior mandible and may be associated with an unerupted tooth (Figure 2). Radiographically, ameloblastic fibro-odontoma/ameloblastic fibrodentinoma appear as well-circumscribed radiolucent lesions whose radiodensity is compatible with the tooth structure.…”

“…4 These malignant entities have been recognized and described since the first WHO edition. 3,4 Malignant transformation is not observed for odontomas. Few studies have investigated the genetic/molecular profile of these tumors.…”