Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Odontogenic and Maxillofacial Bone Tumors

Abstract

The 4th edition of the World Health Organization's Classification of Head and Neck Tumours was published in January of 2017. This article provides a summary of the changes to Chapter 4 Tumours of the oral cavity and mobile tongue and Chapter 8 Odontogenic and maxillofacial bone tumours. Odontogenic cysts which were eliminated from the 3rd 2005 edition were included in the 4th edition as well as other unique allied conditons of the jaws. Many new tumors published since 2005 have been included in the 2017 classification.

Keywords: Gnathic bone tumors; Gnathic conditions; Odontogenic cysts; Update on WHO Classification of odontogenic tumors; WHO Classification; odontogenic tumors.

Fig. 1

Sclerosing odontogenic carcinoma with slender cords of epithelium in a desmoplastic stroma (H&E Original mag × 33)

Fig. 2

Sclerosing odontogenic carcinoma where the epithelial component shows minimal cytologicatypia (H&E Original mag × 66)

Fig. 3

Sclerosing odontogenic carcinoma (IHC AE1/3)

Fig. 4

Schematic illustration of BRAF a and Sonic Hedgehog b pathways that are involved in the pathogenesis of ameloblastoma

Fig. 5

Unicystic ameloblastoma with mural infiltration (H&E stain Original mag × 33)

Fig. 6

Primordial odontogenic tumor with primitive ectomesenchymal stroma lined by odontogenic epithelium (H&E stain Original mag × 6.6)

Fig. 7

Primordial odontogenic tumor showing cellular detail of the stromal and epithelial components (H&E Original mag × 33)

Fig. 8

Buccal bifurcation cyst which is typically buccal to an erupting first or second mandibularmolar