Page 789 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

764 CHAPTER 4

VetBooks.ir 4.89 as having varying degrees of malignancy. Non-
neoplastic lesions such as exuberant granulation
tissue and reactive inflammatory lesions can be mis-
taken for tumours by their similar gross appearance.

Differential diagnosis
Dental pulpitis, fracture callus, foreign body granu-
loma, sialodeniasis and fracture haematomas.

Diagnosis
Diagnosis is based on clinical appearance supported
by oroscopy, radiography, CT and histopathological
analysis of biopsies. CT offers by far the most exten-
sive imaging in three dimensions and is a vital tool
in any treatment planning, especially for dental and
osseous tumours of the mouth (Fig. 4.89). Magnetic
resonance imaging (MRI) would be desirable for
soft-tissue lesions where available.

Management
The treatment options are often limited by the
Fig. 4.89 3D surface reconstruction of a pony with a advanced stage of the lesion, the anatomical location,
maxillary sarcoma. which can preclude surgical access, and the few treat-
ment options available to the clinician. The low inci-
dence means that reports of comparative treatment
masticatory pain, hypersalivation and halitosis. of such lesions are lacking in this species. Benign
Aggressive lesions may be associated with secondary dental tumours are excisable, with a low recurrence
dental disease. The gross appearance of many lesions rate, and this may also involve removal of teeth.
is similar and histopathological examination is usu- Non-dental tumours are usually poorly demarcated,
ally necessary for a specific diagnosis. Diagnostic at an advanced stage when diagnosed and adjacent to
imaging including oroscopic examination and three- other vital structures. Benign osteomas and fibro-
dimensional imaging is invaluable. The histological osseous lesions can be treated by radical mandibu-
classification of some oral tumours, especially those lectomy, but the limitations of by-pass feeding in
belonging to the fibro-osseous groups, is highly spe- the horse are almost insurmountable and the welfare
cialised and the classification follows that described implications of radical surgery deem euthanasia to
for such lesions in human patients. Lesions are be more appropriate in many cases. Radiotherapy is
defined according to their tissue origin (i.e. as being available in a few centres and is most appropriate for
derived from dental tissue, bone or soft tissues) and easily accessible lesions no larger than a few cm .
3

DISEASES OF THE SALIVARY GLANDS

The salivary glands of the horse consist of paired on flow rate, which is variable, but up to 50 ml/min
parotid, sublingual and submaxillary glands, of have been recorded in ponies. Salivary gland dis-
which the parotid glands are the largest and produce eases are rare in horses and most are acquired as a
the greatest volume of saliva. Saliva contains elec- consequence of trauma. A single case of congenital
trolytes, the concentration of which is dependent salivary tract atresia has been reported.