SCC is a form of skin cancer that affects the outer layer of skin cells. Ophthalmologically, it can develop in the eyelid margins, the third eyelid (nictitating membrane), or the cornea. It is the most common type of malignant eyelid tumor found in horses, cattle and cats. This disease can also occur (rarely) in other species such as the dog. Due to the altitude and high number of sunny days of our region, SCC is more prevalent amongst animals in Colorado. Color dilute individuals and/or those with nonpigmented regions of skin have a higher predisposition of developing SCC (similar to the way fair skinned people are more susceptible to skin cancer). Thus, limiting major exposure to intense UV light or using protective gear is important. A biopsy and histopathology are necessary in order to definitively diagnose SCC. Treatment and prognosis will depend on the exact location, size and severity of the issue. Without treatment, the disease will undoubtedly progress and can spread to other parts of the body.
We strongly recommend the use of ultraviolet protective masks in horses.