Periocular sarcoid, like sarcoid in other regions, is thought to be caused by a virus. Bovine Papilloma Virus can be found in cells from many of these growths.

Sarcoid near the eye most commonly appears as a hairless thickening of the tissues of the skin around the eye. It can be lumpy or warty. It can also appear as ulcerated, bleeding masses, known as the fibroblasitc type.

Sarcoid around the eye is fundamentally different than the condition elsewhere. It can be very difficult to treat for several reasons. The proximity to the eye means that treatment approaches must not damage the eye itself. There is minimal tissue around the orbit, so surgery cannot be radical- ie. wide tissue margins cannot be taken without leaving deformity of the region and ultimately leading to eye damage.

In tissue studies around sarcoid, it has been found that sarcoids in this region tend to invade surrounding tissues even more aggressively than sarcoid in other areas.

This means that recurrence is common after surgery. The same goes for laser surgery and cryotherapy- all are less effective than they might be in other sarcoid types.

DIAGNOSIS- Your vet can diagnose this condition in most cases by assuming that a mass in this region is highly likely to be sarcoid. Biopsy can confirm this, but it can also "anger" a lesion, making it more aggressive.

TREATMENT- Surgery may be useful for making a periocular sarcoid smaller (debulking) , and thus more amenable to other local treatments. The gold standard for treatment of sarcoid in this area is brachytherapy- irradiation using radioactive implants placed into the tissue. Another fairly successful treatment has been immunotherapy using BCG (Bacillus- Calmette-Guerin). Finally, there is at least a chance that autologous vaccination using sarcoid tissue implanted into the horse's body, can set up an immune rejection of the periocular sarcoid and result in its disappearance.