EEVS Monthly Newsletter



Squamous cell carcinoma (SCC)
Squamous Cell Carcinoma
by Dr. Amanda Wilson

Squamous cell carcinoma (SCC) is a term used to describe a tumor, or cancerous growth. The tumor can occur anywhere on the body that squamous-type cells are present. In horses, the most common site for SCC is the eye and the tissue surrounding the eye. They can occur on the eyelids, the conjunctiva, and the cornea.


Horses with white faces and white eyelids are predisposed to getting SCC, especially Paint and Appaloosa horses. Exposure to UV light (sunlight) also predisposes horses.


As an owner, you may first notice rough, "cobblestone" tissue that is usually pink to red in color on your horse's eye or on the tissue around the eye. While it is not an emergency, if you notice this it is important to have your veterinarian examine your horse's eye promptly to diagnose and appropriately treat the eye.


A biopsy of the tissue is the best chance at arriving at a correct diagnosis. However, your veterinarian may elect to begin treatment based on clinical appearance before the results of the biopsy are received.


Treatment for SCC may involve one or multiple of the following therapies, depending on the tumor's growth characteristics, the tissues involved, and the prognosis for function of the eye:


Surgical excision: surgery to remove the tissues involved. This may be done at the time of biopsy or after. Some SCC tumors require multiple surgeries, depending on their growth characteristics.


Cryotherapy: involves "freezing" the tissues, which slows growth rate. Often used in conjunction with surgery and sometimes with chemotherapy administration. Cryotherapy affects surface tissues only, but can be beneficial in hindering tumor growth.


Laser ablation: surgical method that applies laser to the tissues to slow growth rate.


Chemotherapy: application of chemotherapeutic drugs to disrupt tumor growth. Often, this is done locally into the affected tissues.


Photodynamic therapy: This is a new, but promising method of treatment that requires referral to a facility that performs the procedure. The procedure is costly, but may be an available option for your horse.


It is important to keep in mind that treatment for SCC often requires dedication from you, the owner, and aggressive treatment by your veterinarian. Some horses may have very aggressive tumors that require removal of the eye. Fortunately, most SCC involving the eye are locally invasive but rarely metastasize or spread to other parts of the body.


For white-faced horses that are outside, a good preventative to consider is a Guardian Mask, which is different from a regular fly mask in that it blocks UV rays. 

SCC of lower eyelid after surgical debulking

Dr. Kin and Dr. Wilson performing cryotherapy for SCC
Now Offering!      
We are excited to announce that we are now offering cryotherapy for treatment of squamous cell carcinoma, sarcoids, and other skin growths. Cryotherapy is the local application of cold temperatures to inhibit cellular growth. 
Don't forget Fall booster vaccinations!

Exclusively Equine Vet Services PC
PO Box 721777
OKC, OK 73172
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- Winston Churchill