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.
CONCLUSIONS: 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.

BACKGROUND: The World Health Organization\'s (WHO) chapter on odontogenic and maxillofacial bone tumors provides a global reference for diagnosis of these tumors. In the fifth edition, the inclusion of consensus definitions and development of essential and desirable diagnostic criteria help improve recognition of distinct entities. These are key enhancements since the diagnosis of odontogenic tumors is largely based on histomorphology which is taken in combination with clinical and radiographic appearances.
METHODS: Review.
RESULTS: Despite delineation of diagnostic criteria for ameloblastoma, adenoid ameloblastoma, and dentinogenic ghost cell tumor, a subset of these tumors continues to show overlapping histological features that can potentially lead to misdiagnosis. Accurate classification may be challenging on small biopsies, but potentially enhanced by refining existing diagnostic criteria and utilization of immunohistochemistry and/or molecular techniques in a specific cases. It has become clear that the clinical and histologic features of the non-calcifying Langerhans cell-rich subtype of calcifying epithelial odontogenic tumor and the amyloid-rich variant of odontogenic fibroma converge into a single tumor description. In addition, this tumor shows remarkable clinical, histological overlap with a subset of sclerosing odontogenic carcinoma located in the maxilla. Benign perineural involvement vs perineural invasion is an underexplored concept in odontogenic neoplasia and warrants clarification to reduce diagnostic confusion with sclerosing odontogenic carcinoma.
CONCLUSIONS: While controversial issues surrounding classification and discrete tumor entities are addressed in the WHO chapter, ambiguities inevitably remain. This review will examine several groups of odontogenic tumors to highlight persistent knowledge gaps, unmet needs and unresolved controversies.

BACKGROUND: Adenoid ameloblastoma (AdAM) is a frequently recurrent tumor that shows hybrid histological features of both ameloblastoma and adenomatoid odontogenic tumor (AOT). AdAM is expected to be classified as a new subtype of ameloblastoma in the next revision of the World Health Organization (WHO) odontogenic tumor classification. However, whether AdAM is a histologic variant of ameloblastoma or AOT remains unclear. To establish a new category, genetic evidence indicating the tumor category is necessary.
METHODS: We present a case of a 23-year-old Japanese woman with AdAM who underwent genetic/DNA analysis for ameloblastoma-related mutation using immunohistochemical staining, Sanger sequencing, and next-generation sequencing (NGS) analyses with reliable clinicopathological evidence.
RESULTS: Immunohistochemical expression of BRAF p.V600E was diffusely positive for both ameloblastoma- and AOT-like components. Sanger sequencing and NGS analyses showed missense mutations in BRAF p.V600E (c.1799T > A), a gene that is commonly altered in ameloblastomas but not in KRAS, another gene associated with AOT.
CONCLUSIONS: This case report is the first to provide genetic evidence on the ameloblastomatous origin of AdAM with a BRAF p.V600E mutation. A larger series of AdAM groups\' molecular testing is needed to aptly classify them and prognosticate the best treatment.

BACKGROUND: A recent systematic review published in Head and Neck Pathology found that 3.8% of dentinogenic ghost cell tumors harbor duct-like/ cribriform architecture. Herein we discuss this finding regarding the differential diagnosis of this tumor with adenoid ameloblastoma.
METHODS: A critical review of some microscopic findings reported in a recent paper published in the Head and Neck Pathology Journal was done.
RESULTS: Although there are overlapping microscopic features with dentinogenic ghost cell tumor, adenoid ameloblastoma is distinguished by the combination of duct-like structures and whorls/morules. In our opinion, at least some cases previously diagnosed as dentinogenic ghost cell tumors may now be more accurately classified as adenoid ameloblastoma.
CONCLUSIONS: We conclude that a reassessment of dentinogenic ghost cell tumor cases using the diagnostic criteria proposed by the new WHO classification of Head and Neck Tumors (2022) is warranted.

Adenoid ameloblastoma is a hybrid odontogenic tumour showing histopathological features of both ameloblastoma and adenomatoid odontogenic tumour (AOT), with approximately 40 cases reported in the literature. The aims of the report are to illustrate the diagnostic challenges of adenoid ameloblastoma using three new cases and to analyze evidence in literature to consider adenoid ameloblastoma as a new sub type of ameloblastoma. A literature review was performed with the key words-adenoid ameloblastoma, hybrid/composite odontogenic tumours, hybrid ameloblastoma and adenomatoid odontogenic tumour, ameloblastoma with inductive changes, dentinoid and dentinoma to select the cases compatible with the diagnosis of adenoid ameloblastoma. Out of the 40 cases reported in literature, 31 cases with sufficient information and 3 new cases were analyzed. Out of the 34 adenoid ameloblastomas majority of tumours (76.5%) occurred in adults with age ranging from 25 to 55 years. Slight female predilection with a male:female ratio of 0.9:1 was observed. Approximately, 64.7% occurred in the mandible. Radiologically, 82.4% of adenoid ameloblastomas presented as radiolucent lesions while 47.1% occurred with ill-defined margins and cortical perforation at diagnosis. Histopathologically, 70.8% of tumours presented as plexiform ameloblastomas, while duct like structures/glandular structures were the commonest feature supportive of adenomatoid odontogenic tumour observed in overwhelming majority of 95.9% of adenoid ameloblastomas. 91.6% of tumours showed inductive change in the form of dentinoid. Further, 45.4% of the tumours developed at least one recurrence following surgical excision. The report presents literature review based evidence to show the existence of adenoid ameloblastoma, which is demographically similar to conventional ameloblastoma but with histopathological differences and presenting with higher rate/multiple recurrences, indicating its biological aggressiveness. Thus, we would like to propose the inclusion of adenoid ameloblastoma as a sub type of ameloblastoma in the next revision of the WHO odontogenic tumour classification.

Odontogenic tumors are rare entities, often derived from the epithelial remnants in the gnathic bones following odontogenesis. This brief manuscript will seek to address recent developments pertaining to odontogenic tumors as well as particularly uncommon odontogenic tumors and the difficulties in their diagnosis.