If your horse is sporting a new skin growth, the problem may be a sarcoid. This type of benign tumor is among the most common skin cancers in horses, mules and donkeys.

Some sarcoids look like sores or ulcers that bleed before scabbing. Others present as fleshy or warty growths.

The cause of sarcoids is still a mystery, but a virus that causes similar growths in cows may also affect horses. While sarcoids don’t spread, they can invade surrounding tissue. Your veterinarian might recommend surgically removing the mass, freezing it off, destroying it with a laser or administering topical chemotherapy. But because sarcoids can recur after removal, some veterinarians opt not to treat unless the tumor becomes a nuisance to your horse.

Other problems can mimic sarcoids, so it’s best to contact your veterinarian if any strange lumps or sores crop up.