What they are:
Sarcoids are unfortunately very common, being the most common skin tumour affecting horses. Sarcoids can have a varied appearance and will appear as anything ranging from a hairless area of skin to a big multi-lobed ulcerated mass. It is often difficult to identify sarcoids as they have such a variety of common appearances.
Sarcoids can show up anywhere on the body, but are most commonly found on the abdomen, on the inside of the back legs, around the sheath, on the chest and around the face. It is also common for them to occur in old scars. Sarcoids are difficult to classify.
While they can have an innocent enough appearance and don’t spread to other parts of the body, they usually ultimately destroy the tissue that surrounds them.
This is why some vets consider them to be a form of skin cancer and others do not.
Some vets prefer to use a ‘wait and see’ approach with sarcoids, as often they recur after removal, so putting the horse through a procedure is not worthwhile. However, if the sarcoid is large or causing trouble to the horse it may be removed by cryotherapy (freezing of the sarcoid) or surgically. Some vets will try injections into the sarcoids of immune-stimulating substances or chemotherapeutic drugs before they resort to a surgical approach. It is in fact likely that your horse will receive a number of different treatment modalities, and often the treatments will be combined. Unfortunately, however, sarcoids have a bad habit of recurring and can come back even bigger than before, so no treatment is a 100% guarantee that the sarcoid is gone.