A Systematic Review of Adenoid Ameloblastoma: A Newly Recognized Entity

Abstract

Background: Recently, a new odontogenic tumor has been described, the so-called adenoid ameloblastoma (AdAM). The aim of this review was to determine the clinical and imaging features of AdAM and to describe its main histopathological findings.

Methods: The systematic review included published cases with a diagnosis of AdAM in the gnathic bones, which had sufficient clinical, imaging, and histopathological data to confirm its diagnosis. The following histopathological diagnostic criteria were adopted: presence of ameloblastoma-like components, duct-like structures, spiral cellular condensations, and a cribriform architecture.

Results: Fifteen articles, corresponding to 30 cases of AdAM, were selected. Most cases affected men (63.3%), with a slight preference for the mandible (16:14) and the posterior region of gnathic bones was the most commonly affected site. The mean age at diagnosis was 40.8 years. Clinically, the lesions usually presented as a swelling (53.3%) and, radiographically, as a well-defined radiolucency (33.4%). Surgical resection (40%) was the most frequently adopted treatment and recurrence occurred in 30% of cases. Microscopic examination showed cribriform areas in most AdAM cases (93.3%); duct-like structures and spiral cellular condensations were seen in 100% of the cases.

Conclusion: The small number of reported cases, the existence of erroneous diagnoses, and the adoption of initial conservative management make it difficult to determine whether AdAM has a higher risk of recurrence or more aggressive biological behavior than conventional ameloblastomas.

Keywords: Adenoid ameloblastoma; Ameloblastoma; Dentinoid; Odontogenic tumor.

Fig. 1

Flowchart of the study selection process

Fig. 2

Geographical distribution of adenoid ameloblastoma cases selected for the present systematic review

Fig. 3

Anatomical location of the cases diagnosed as adenoid ameloblastoma. The percentage of cases between the arrows indicates tumors located in the anteroposterior region of the mandible or maxilla

Fig. 4

Histopathological features of adenoid ameloblastoma. a Presence of an ameloblastomatous plexiform pattern and cribriform arrangement in solid areas (100×). b Spiral epithelial structures and clear cells (200×). c Duct-like structures containing scant eosinophilic material (400×). d Dentinoid material near some clear cells (400×)