Sarcoids

     April 2003 was bringing thoughts of spring, warmer weather, and trailriding!  My friend Gaye called asking me to trailer over to Wolf Creek for a ride with Danny and her. I noticed that Little Man had developed a wart right below his left ear, and I was concerned about the fact that it was right where his browband could irritate it. Sure enough, after we unsaddled and I removed Little Man's bridle, the wart was bleeding a bit. Fly season hadn't come upon us with a vengence yet, so I figured the sooner we got the growth removed, the better off my horse would be.

     One look and the vet informed me that Little Man had a sarcoid. It took awhile for me to recall an article I'd read months earlier about sarcoids. The pictures which accompanied it sprang to mind; they were pretty grim.

     After some discussion, my vet decided to apply XXTERRA, a bloodroot cream. It's a 10 minute ride home; as I walked my horse to the barn, I noticed that the sarcoid has already fallen off. Only a small trickle of blood ran from the spot. Within days, the whole sarcoid area developed a thick, brown scab. It oozed blood and some pus. The scab remained for about 4-5 weeks; when it fell off, the area looked pretty good.

     If you find an unusual growth on your horse, chances are it's not a sarcoid. I strongly suggest having the vet confirm the diagnosis. At this point, I am concerned in that Little Man has several more small sarcoids in the general area. The vet and I agreed that we would keep an eye on them for the time being; one major factor is that we are in the midst of the "fly season".

     Here are some things I've learned about sarcoids:

     Sarcoids develop from a specific cell in the skin called the fibroblast. The most common sites where sarcoids develop are the head, ears, limbs, and ventral abdomen.

     The 4 major forms of sarcoids observed are the flat (occult), verrucous (warty), fibroblastic (proud flesh) and mixed form. The flat sarcoid appears as a circular area of hair loss and is limited to the superficial layer of the skin. These lesions usually remain static or regress spontaneously with time. The verrucous sarcoid, as the name implies, appears warty or cauliflower-like. It may grow, remain static, regress with time, or change into a fibroblastic sarcoid whereby trauma to the lesion may enhance this change. The fibroblastic sarcoid is the most aggressive type . The surface is often ulcerated, has the tendency to bleed when the horse rubs or bumps this area, and often will become infected. The only way to find out if the mass is a tumor, and if so, what type of tumor, is by doing a biopsy. This is a benign procedure that can be performed on a sedated horse with the help of local anesthesia.

     Many treatments have been tried for the removal of sarcoids but none of them have been routinely successful. The best initial treatment is to wait, as a large percentage of sarcoids will regress spontaneously with time if left alone. However, if the sarcoid grows in size or changes into a fibroblastic sarcoid, treatment is recommended. Surgical removal is a viable option, however, the major problem with surgery is the chance for recurrence. Therefore, surgical removal is often combined with cryosurgery or immunotherapy, even though these latter treatments can be performed independently. In cryosurgery, application of liquid nitrogen eliminates the lesion. For large sarcoids, however, this treatment should be repeated several times, as one treatment may not completely remove it. The most common immunomodulator used for treatment of sarcoids is BCG (Bacille Calmette-Guerin), which is derived from the cell wall of a mycobacterium. By injecting this foreign protein into the sarcoid, the horse’s immune system will try to eliminate this foreign protein, and in doing so will also eliminate the sarcoid. This treatment remains controversial as fatal reactions (anaphylaxis) have been reported. Radiation therapy is a good alternative if the lesions cannot be removed by surgery due to anatomical location.

     If a non-healing skin lesion is observed on your horse, a veterinarian should be consulted. Subsequently, an appropriate treatment plan should be discussed if a definitive diagnosis of sarcoid is made.