Page 787 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

762 CHAPTER 4

VetBooks.ir Management that appears to offer a reasonable prognosis in the
absence of ongoing disease, especially where there is
Freeing of the articulation by removal of one sec-
tion of the stylohyoid bone has been attempted
appear to form a bony union with callus formation,
but the prognosis is guarded in many cases. unilateral involvement. Fractured stylohyoid bones
Keratohyoidectomy, which disarticulates the although it is unclear in such cases whether the frac-
afflicted side, is a more straightforward procedure ture is associated with the temporohyoid syndrome.

ORAL NEOPLASIA

INTRODUCTION neoplasm on other tissues. Dental tumours although
invariably benign may be locally invasive and may
Tumours affecting the oral cavity can be of dental, disrupt adjacent tissues by their expansion.
boney or soft-tissue origin and are relatively rare Dental tumours, including ameloblastomas
compared with other species. There are numerous (Fig. 4.83), both complex and compound odonto-
individual case reports to be found in the literature, mas (Fig. 4.84), mandibular tumours of non-dental
but few series involving large numbers. Frequently, origin that include osteomas, ossifying fibromas
oral tumours are detected incidentally during a rou- and squamous cell carcinomas, can all result in
tine oral or dental examination and they are often at gross changes to the dental apices and reserve
an advanced stage, limiting the options for treatment crowns. This may be accompanied by swelling
and rendering the prognosis for complete remission of the affected alveolar bone, with increased or
to be guarded. decreased radiopacity. The immature cells in some
dentally-derived tumours are variably mineralised,
DENTAL NEOPLASIA and they are usually well circumscribed.

Dental tumours may be epithelial in origin, or ORAL TUMOURS OF NON-DENTAL
odontogenic such as cementomas, ameloblastomas, ORIGIN
odontomas or other calcifying epithelial odontogenic
lesions. Mesenchymal odontogenic tumours include Case reports describing oral tumours of non- dental
myxomas and dentigerous cysts. These tumours origin include mandibular ossifying fibromas
are classified according to the inductive effect of the (Fig. 4.85), osteomas, osteosarcomas, fibrosarcomas

4.83 4.84

Fig. 4.83 An ameloblastoma in the cranial lower jaw Fig. 4.84 Radiograph of a compound odontoma
about to undergo surgical resection (arrow). within the paranasal sinuses (arrows) – a rare dentally-
derived tumour.