Skin Tumors in Horses

April 25, 2011 (published)

The skin is the most common site for tumors in horses and today we are going to talk about some skin tumors and their treatments. The most common skin tumor is called a sarcoid and there are several different types of it. Sarcoids are non-malignant but can invade local tissue and cause a lot of damage. Sarcoids can appear flat, warty, or nodular and usually affect the head, neck, ventral body, and the legs. Also, sarcoids can develop at wound areas, even surgical wounds.

It is important for your vet to biopsy any skin tumor because many tumors can look similar but require different treatments. Sarcoids can be removed surgically but it has been shown that 15-82% of these tumors will recur so surgical removal should be performed cautiously. Some of these sarcoids have tissue that extends far around the tumor and so it is sometimes difficult to remove the entire tumor even though it may appear it was all removed. If the entire tumor is not removed, it can certainly recur and for this reason, it is always a good idea to inject a drug around the incision after removal to prevent regrowth. Most of the drugs that are injected into these tumors are cancer drugs so it is important to be careful with these drugs and for this reason, your vet will always inject these drugs and not dispense them. A common drug used for this is Fluorouracil (5-FU) as it is inexpensive and seems to be effective. There are many other treatments for sarcoids including cryotherapy, which is freezing the tumor. Numerous creams are available to apply to these tumors and even Crest toothpaste has been applied to sarcoids in horses with some success. Join us next time for more on equine skin tumors.

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