The fourth edition of the head and neck World Health Organization blue book: editors' perspectives

Controversies in Odontogenic Tumours: Review

“…4,5 Metastasising ameloblastomas were reclassified as benign tumours rather than malignant odontogenic tumours as these tumours show benign histopathology in spite of their metastatic potential, rendering them difficult to differentiate histopathologically from conventional ameloblastomas. 2 Based on the innocuous nature of peripheral ameloblastomas (PAs), Philipsen et al questioned whether such lesions were analogous to solid multicystic ameloblastomas (SMAs) or hamartomatous lesions. 10 Indeed, the biological behaviour of a PA has been deemed more indicative of a hamartomatous proliferation or persistent hyperplasia than neoplasia.…”

“…18 For this reason, in 2005 the WHO categorised OKC as a benign odontogenic neoplasm and changed the nomenclature of OKC to KCOT. 2 This classification was not fully accepted and many authors continued using the older terminology. 12,19,20 Nevertheless, although PTCH gene alterations can be found in up to 85% of OKCs associated with nevoid BCC syndrome, they are only found in 30% of sporadic cysts.…”

“…24 Hence, these lesions were reclassified as cystic lesions rather than odontogenic tumours in the 2017 WHO classification. 2,21 While both OKCs and orthokeratinised odontogenic cysts are considered developmental cysts, OKCs behave more aggressively. 20 …”

“…tooth development) and include a wide variety of lesions ranging from hamartomas to non-neoplastic tissue proliferations and both benign and malignant neoplasms. 1,2 Due to this wide range of biological behaviour, there is currently much debate regarding the pathogenesis, classification and clinical and histological variations of odontogenic tumours. 1 The present review aimed to provide insight into different controversies and recent developments in this field, particularly with regards to the recent 2017 World Health Organization (WHO) classification of odontogenic tumours.…”

“…1 The present review aimed to provide insight into different controversies and recent developments in this field, particularly with regards to the recent 2017 World Health Organization (WHO) classification of odontogenic tumours. 2 Awareness of such controversies may aid in a better understanding of these pathological entities as well as enhancing their diagnosis and management. A brief overview Nevertheless, researchers have argued that classifying odontogenic tumours as either benign or malignant does not encompass the reported range of behaviours shown by these lesions.…”