Squamous Cell Carcinoma

Oral squamous cell carcinoma. Courtesy of T. Scase

neoplastic

Papilloma and Squamous Cell Carninoma of Epiglottis (Courtesy of Alun Williams (RVC))

• 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.
  

  Bovine abomasal lymphoma. (Courtesy of Elspeth Milne
• 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