Learn About Those Lumps and Bumps - Sarcoids on Horses

Although they can look alarming, sarcoids are fairly common. These tumors can take a few different forms, and don’t generally harm the horse unless they are in a place that is chaffed by harness or saddlery, or that rubs when the horse moves, such as between the back legs or under the tail. While they can look like warts caused by papillomavirus, they aren’t the same. They can also look like proud flesh, excess granular buildups of skin cells that grow on the sites of injuries.

Nor do they fit the description of a cancerous tumor, although this has been debated.

Other Names for Sarcoids:

Warts (incorrectly), tumors, neoplasm

Symptoms:

Sarcoids can take a number of different forms. They can grow singly, or in clusters. They may be long and pendulous, like a finger, or they may be flat and irregularly shaped. They may also be circular or contain several nodules within the boundary of the sarcoid. Some may appear dry and scaly, while others may weep or bleed. Some appear to be under the skin, and covered by the hair coat, while others may appear more scab like and growing from the surface of the skin. Because of these variations, it’s easy to assume they are some other type of tumor--either more serious or benign.

Sarcoids are generally found under the tail region, between the back legs, on the face, under the belly and on the ears, although they can grow almost anywhere. They may develop where the horse has had a skin injury. Some horses may only have one sarcoid, while others may have multiple tumors on various places on its body or several types.

Causes:

The Merck Veterinary Manual states that the culprit is most likely Bovine papillomavirus (BPV), primarily types 1 and 2. It’s thought that flies may be the carrier of the virus, and that it is transmitted when a fly lands on the site of a skin lesion. The virus may also be transmitted through shared equipment or when a wound is exposed to dirt in an infected pasture. The lumps themselves are made up of collagen producing skin cells, that grow just beneath the top layers of the skin. Unlike cancer, they do not spread to other tissue such as organs. Some horses may be genetically predisposed to the condition. Many people feel gray horses may get more sarcoids, or they simply may be more obvious on gray horses.

Diagnoses:

If your horse has sarcoids, especially if they appeared suddenly or are growing quickly, your veterinarian may take a biopsy of the tissue. This way, it can be determined if your horse has relatively benign sarcoids that can be treated, or if cancer is a concern and more aggressive treatment is needed. Sometimes, the biopsy can make the sarcoids worse. But once a diagnosis has been confirmed, treatment may begin. Sometimes sarcoids go away on their own. But most don’t and the sooner treatment begins, the better chance there is that they can be minimized. Most will never go away completely, even with treatment. Some people will try home remedies, but this will probably only delay the time until proper treatment can begin. Home treatment can easily do more harm than good.

Treatment:

Because there are many forms of sarcoids, there are many ways of treating them. Some may be removed surgically, and the area sutured. Some can be ‘strangled’ with bands until they fall off. Cryotherapy, radiotherapy or laser surgery may be used. And be aware, that often the sarcoids may grow back if only surgery is used. Topical creams such as retinoids may be effective. Antiviral drugs may be tried. Veterinary medicine is advancing and there are some new treatments being tested. Talk about the different options available with your veterinarian.

Prevention:

Sarcoids appear on horses of every size, color, age, sex, breed and type, sometimes with no apparent reason. Since flies may carry the virus, taking care to keep flies away from injuries such as punctures, cuts and scrapes makes sense, as well as keeping these areas clean.