Squamous Cell Carcinoma in Animals
By Dr. Maqsood Alam, VetVid, AltoVet, Toa Payoh Vets, VRCC.
Sources: .flv, .mp4
Edition: 2008, 2010, 2011
Duration: 3:00 - 5:00 min., variable.
Squamous cell carcinomas (SCC) are malignant tumours commonly seen in the cat, dog, horse and cow. They are most likely to develop in non-pigmented areas of the skin as there is a known association between their development and exposure to UV light. The tumours are normally slow to metastasize but may be locally invasive.
There are two forms of the neoplasm:
* Proliferative — cauliflower-like lesions
* Ulcerative — ulcerative lesions
Histologially, the tumours are formed from epidermal cells with varying degrees of squamous cell differentiation.
Squamous cell carcinomas of the oesophagus are most notably seen 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. Oesophageal SCC forms part of upper alimentary tract carcinoma complex.
Cutaneous SCC's are the second most common neoplasms in the horse. Contact withpenile smegma is thought to be an a predisposing cause. They are most commonly located in the penile or clitoral regions and on non-pigmented skin. Lesions are progressive and potentially locally invasive. They may be ulcerative or proliferative and secondary infection is often present, producing a foul odour. Complete surgical excision is the gold standard treatment, but adjuncts may be required. Masses located
around the eye may need prompt specialist treatment to save the eye.
SCC of the stomach is the most common gastric tumour in the horse. It has the appearance of a large cauliflower-like mass and affects the pars oesophagea. It metastasises and spreads transcoelomically.
Rarely SCC can form in the nasal cavity of the horse. These originate from the maxillary sinus and cause facial distortion, tissue necrosis and airway obstruction.
A serosanginous or mucopurulent, odorous nasal discharge may be present.
Additionally, there is thought to be an association between the ingestion of bracken fern carcinogens and the malignant transformation of papillomas to squamous cell carcinomas in cattle.