Odontogenic tumours in the dog and cat

Objective: Odontogenic tumours in the dog and cat, as well as in other domestic animals and in man occur rarely and can be difficult to diagnose. In the present study a great number of canine and feline odontogenic tumours were investigated histopathologically and classified to provide an appropriate basis for the evaluation of these tumours. Material and methods: In a retrospective study of a total of 1390 canine and 317 feline oral tumours from the years 1977 to 2007, the tumours of odontogenic origin were selected, characterized histopathologically and classified according to the current human WHO-classification of odontogenic tumours (2005) and the current veterinary WHO-classification of odontogenic tumours (2003). Results: 18% (n = 250) of the canine and 3.2% (n = 10) of the feline oral tumours proved to be of odontogenic origin. They could be divided into benign (epithelial, epithelial and ectomesenchymal, ectomesenchymal) and malignant (carcinomas and sarcomas) odontogenic tumours with a total of 12 different entities. The odontogenic fibroma was the most common canine (n = 167) and feline (n = 4) odontogenic tumour. The second most common odontogenic tumour for canines was ameloblastoma (n = 74) and that for felines was ameloblastic fibroma (n = 2). Four of the 12 entities could be classified according to both WHO-classifications of odontogenic tumours. Seven and two of the 12 entities could only be classified according to the current human WHO-classification and veterinary WHO-classification, respectively. Conclusion and clinical relevance: The prognostic evaluation of tumours is of the greatest clinical relevance and calls for an absolutely certain diagnosis. Particularly in the case of the rare and histomorphologically complex odontogenic tumours the current veterinary WHO-classification does not meet this requirement and needs to be revised and extended. The human WHO-classification proved to be more efficient when compared to the veterinary one.