Skin cancer in horses is actually a relatively common affliction, particularly for light-colored animals. This is why the term "grey horse melanoma" has become standard vocabulary for horse owners, breeders and competitors.
Identifying Equine Melanoma
Most equestrians have seen horse melanoma before, even if they do not know the name for it. A melanoma is a hard nodule or lump, usually black or dark grey in color, underneath the horse's skin. It is not painful to the touch and it does not leak any fluid, but it does indicate skin cancer in horses.
Melanoma is a form of skin cancer that is often fatal to humans. This is because the cancer cells often spread (or metastasize) to other areas of the body, leading to multiple organ involvement. In the horse, however, the cancer most often stops in the skin.
They are most commonly grouped around the eyes, ears or rectum, though they are also found on the flank, abdomen and jugular groove. They are often discovered while the horse owner or handler is grooming the horse and discovers a strange lump underneath the horse's skin.
Multiple Melanomas
As mentioned above, melanoma metastasis is not particularly common in horses, as the cancer and spotting on a horse's body is not cause for panic. However, multiple melanomas are common in light-colored horses, and it is possible to find five, six or even ten of the hard round lumps on a horse's body.
The problem is that the more melanomas spread, the more likely they are to disrupt the horse's life and cause serious problems. Since they can form close to vital organs or in uncomfortable places, it is important for horse owners to keep a close watch on their animals. For example, lumps on a horse's rectum can lead to problems with urination, defecation and breeding.
Additionally, although equine melanoma is not painful, it can cause discomfort if the lumps are located in the saddle or bridle area. They can become abraded and inflamed because they force the skin to protrude and may cause friction between the skin and tack. If this is the case, gauze bandages can offer a temporary solution.
Diagnosing a Malignant Melanoma
To determine whether a horse has a malignant melanoma, the veterinarian will want to take a small biopsy of the lump. He or she will be able to identify the type of cells through a microscope and with laboratory tests. From there, the veterinarian will determine the best course of action.
Although malignant melanoma is uncommon in horses, it is important for horse owners to contact a veterinarian immediately. Early detection is the best way to keep horses safe.
Skin cancer in horses can seem like a devastating illness, but in most cases it will cause no problems other than cosmetic blemishes. Horse owners should watch out for:
- Spreading of equine melanoma
- Difficulty defecating or urinating
- Problems with seeing or hearing
- Signs of organ failure
- Listlessness or change in personality
These might be signs of a malignant melanoma causing damage to the horse. Otherwise, horse owners should simply keep an eye on lumps and keep in close communication with a competent veterinarian.
Treating Equine Melanoma
The most common treatment for horse melanomas is surgical removal, although it is not always necessary. If lumps on a horse are not causing any problems, many veterinarians feel it is best to leave it alone. Unfortunately, if the vet does not excise the entire lump, the remaining cancer cells may "activate" and spread more quickly to other areas of the body.
The best thing for horse owners to do is discuss options with a veterinarian. He or she can offer suggestions and provide seasoned advice for dealing with skin cancer in horses.
Laura Thompson - Laura Thompson is a horseback riding instructor and freelance writer living in Houston, Texas. She is proud to be the feature writer for ...
Join the Conversation