Adenoid ameloblastoma (AA) was recently recognised as a separate tumour type in the most recent World Health Organisation (WHO) classification of head and neck tumours. This decision has been considered controversial by several groups, who have described AA as a subtype of ameloblastoma, a hybrid odontogenic tumour or to fall within the spectrum of other recognised odontogenic tumours, including dentinogenic ghost cell tumour and adenomatoid odontogenic tumour. Here we review the reasons for the WHO decision to classify AA as a separate tumour type. We also critique molecular and histological findings from recent reports published since the WHO classification. While acknowledging that the classification of tumours is constantly evolving, the balance of current evidence suggests that AA should remain a distinct tumour type, and not a subtype of ameloblastoma, pending further molecular characterisation.

UNASSIGNED: Although the uncommon dentinogenic ghost cell tumour (DGCT) is a benign entity, it possesses the ability to cause widespread destruction of the jaws and to recur after bone-preserving therapy. Hence, clear margins should be achieved upon surgery, and reconstruction techniques must often be used to restore osseous defects. However, this can be challenging in cases with involvement of the temporomandibular joint (TMJ), and especially in children.
UNASSIGNED: We present a case of a DGCT in a 12-year-old boy with wide infiltration of the mandible and the TMJ. A two-staged reconstructive approach was performed. Upon primary surgery, tumour-free margins were obtained and mandibular anatomy was restored using an iliac crest graft and an alloplastic condyle implant for temporary TMJ reconstruction. In a second step 5 months later, having received a customized TMJ prosthesis consisting of a fossa and a condyle component, the TMJ was completely replaced for definitive reconstruction.
UNASSIGNED: A customized TMJ prosthesis could be a solution for reconstruction of the TMJ in children. However, the further course with respect to growth disturbances must be evaluated upon short-term follow-ups and might require additional corrective interventions.

Ectopic odontogenic tumours are rare and difficult to diagnose. Consequently, they are occasionally misdiagnosed as other tumours and overtreated. Dentinogenic ghost cell tumours (DGCTs) are odontogenic neoplasms characterised by a CTNNB1 mutation, ghost cell appearance, and dentinoid-like calcification. Herein, we present a case of ectopic DGCT on the floor of a patient\'s mouth, providing reliable clinicopathological and genetic evidence of its odontogenicity for the first time.
A 72-year-old man presented with painless sublingual swelling. Imaging revealed a multi-lobulated, solid-cystic mass on the floor of his mouth. Cytological evaluation showed folded epithelial clusters composed of basaloid cells, keratinised material, and calcification. Histological analysis revealed a multi-cystic, cribriform to solid nest, with an odontogenic satellate reticulum-like epithelium, including ghost cells and dentinoid matrix deposition. Immunohistochemical analysis found that CK19, CK5/6, bcl-2, and p63 were diffuse positive, β-catenin was focal positive in the nuclei, and the cells in the dentinoid matrix were positive for DMP1. The CTNTTB1 mutation was detected, leading to the final diagnosis of ectopic DGCT. There was no recurrence during the 6-month follow-up.
Overall, we have presented a comprehensive clinical overview of DGCT and identified its pathological and genetic features. This report will aid in the recognition of this rare disease in the future and help to avoid misdiagnosis and overtreatment.