An orderly approach to the study of odontogenic tumours in animals.

In this paper odontogenic tumours in animals are discussed with the aim of developing a sound basis for further work in this relatively poorly understood field. The following recommendations are made: (1) Odontogenic tumours should be classified according to whether they are of epithelial, mesenchymal or of mixed epithelial and mesenchymal origin, rather than based on inductive changes. (2) The clinical behaviour implied by ameloblastoma, ameloblastic fibroma and odontoma should be carefully considered before these terms are incorporated into the diagnosis of any odontogenic tumour. (3) Caution should be exercised in designating specific odontogenic tumours in animals as being the counterpart of human tumours until their histopathological features and clinical behaviour have been proved to be equivalent. (4) Only tumours that exhibit the typical features of the basal cell layer of ameloblastomas should be designated as ameloblastomas. (5) Ameloblastic epithelium should not be used when odontogenic epithelium is intended. (6) These recommendations should be substantiated by reviewing odontogenic tumours in animals, although doing so will be difficult because of their rarity.