neoplastic
- Squamous cell carcinomas are the malignant equivalent of the papilloma and may arise anywhere within the oropharynx.
- Those arising over the tonsil (squamous carcinoma of the tonsil or tonsillar carcinoma) are very malignant, invading adjacent tissues and metastasising early.
- Squamous carcinomas of the tongue (especially in cats) can also behave in a very malignant fashion. Those at more rostral sites, e.g. on the incisor gingivae, are less likely to metastasise early although they may be locally aggressive.
- Squamous cell carcinomas of the oropharynx in cattle are commonly seen as part of an upper alimentary tract carcinoma complex.
- Squamous cell carcinoma is thought to develop from papillomas in cattle in association with ingested carcinogens in bracken fern.
- Squamous cell carcinomas of the oesophagus are occasionally seen in other species, notably in the cat, where the tumour tends to infiltrate around the oesophageal wall resulting in a “ring carcinoma”.
- The affected cat has progressive difficulty in eating and swallowing.
- Forms part of Upper Alimentary Tract Carcinoma Complex
- The most common gastric tumour in the horse.
- Affects the pars oesophagea.
- Take the form of a large cauliflower-like mass.
- Metastasises, and spreads and transcoelomically.
Nasal Cavity
- In cats they arise mainly from nasal vestibule
- In horses they originate mainly from maxillary sinus
- Most common nasal tumour
- Serosanquineous or mucopurulent, odourous nasal discharge
- Tissue necrosis
- May cause airway obstruction or facial distortion