Ameloblastomas: current aspects of the new WHO classification in an analysis of 136 cases

Abstract

Introduction Ameloblastomas are neoplasms that have inspired great controversy and clinical interest; their incidence, radiographic features, treatment and behavior are still discussed quite often in the literature. In 2017, the classification of these lesions underwent modifications in terminology with the introduction of prospective views based on updates in current genetic studies. Objective To describe the most important features of the new classification, as well as to evaluate the prevalence and the clinical and radiographic characteristics of 136 ameloblastomas. Methodology The clinical-pathological characteristics of 136 patients diagnosed with ameloblastoma in two large hospitals in São Paulo were analyzed. All the hematoxylin-eosin (HE) stained slides were reviewed using an optical microscope (Olympus Cover) and tumors were classified according to the new WHO criteria (2017). Two independent evaluators analyzed the slides; in cases where there was disagreement a third evaluator was used and the result was established in consensus. Results 71% of the lesions were of the conventional type, the predominant histopathological pattern being plexiform (40%), 72% of the tumors showed cortical expansion, and 84% had a radiographic pattern of the multilocular type. The treatment of choice in most cases was segmental resection (45%) and recurrence was present in 13% of the cases. Conclusion Studies with clinical-pathological correlations will be necessary in the near future, in order to provide new therapies that are more effective and conservative, improving the quality of life of patients effected.

Enucleation and surgical stent as a treatment strategy for a large unicystic ameloblastoma: Case report and review of literature

“…Ameloblastoma is a benign neoplasm of odontogenic origin with locally invasive characteristics and high recurrence rate [ [1] , [2] , [3] , [4] ]. Although it is slow-growing, it tends to attain a considerably large size causing severe facial disfigurement and functional implications [ 3 , [2] , [3] , [4] ]. It was first reported by Cusack in 1827 and named by Ivy and Churchill in 1930 [ 5 ].…”

“…Though ameloblastoma is believed to originate from the cells of dental lamina [ 12 ], several etiological factors including local trauma, inflammation, nutritional deficiency, irritation from extraction, and dental caries have been proposed. It is also proposed to originate from the remnants of odontogenic epithelium and lining of odontogenic cysts [ 3 , 13 ]. A recent theory has also elaborated the role of genetic mutation [ 3 , 14 , 15 ].…”

“…It is also proposed to originate from the remnants of odontogenic epithelium and lining of odontogenic cysts [ 3 , 13 ]. A recent theory has also elaborated the role of genetic mutation [ 3 , 14 , 15 ].…”

“…In 2005, the World Health Organization classified ameloblastoma into multicystic (91%), unicystic (6%), peripheral (2%), and desmoplastic (1%) subtypes based on the histopathological features and anatomical location [ 6 , 16 ]. A recent classification has categorized into conventional (85%), unicystic, and peripheral (1%) types [ 3 , 17 ].…”

“…The unicystic ameloblastoma is a neoplasm with cystic involvement of the ameloblastic epithelium, and the tumor grows into the lumen and fibrous connective tissue [ 16 ] It is classified into luminal, intraluminal, and mural subtypes [ 3 ]. It is the second-most common type of ameloblastoma (5–10%), is associated with younger patients and sometimes with unerupted teeth.…”