Confronting the grey area of melanomas
How to recognise and treat melanin-linked tumours
As the owner of a grey horse, the link between greys and tumours under the skin has always been at the back of my mind, and even more so as my hunter Max gets older.
Veterinary studies have shown that around 80-85pc of grey horses over the age of 15 will develop tumours known as melanomas.
Their development is thought to be linked with melanin, the pigment that makes some skin darker than others and which is abundant in the skin of grey horses.
Melanomas are solid, hard, usually round black tumours that are typically found under the tail and around the anus, on the head below the ear and behind the jaw bone. They are sometimes found on the genitalia, less frequently on the limbs and neck and occasionally on the eyelid or within the eye. While melanomas in humans, often referred to simply as skin cancer, are extremely serious, spread rapidly internally and have a poor prognosis, equine melanomas are less worrying.
Vet Sue O'Doherty, from the Horse Happy Veterinary Service in Co Wicklow, is often asked about melanomas in grey horses.
"Melanomas in horses are not to be confused with melanomas in humans as they are rarely malignant," says the vet. "Generally, melanomas in horses do not metastasise or spread in the same way.
"The significance of melanomas in horses is more to do with their location on the body and what impact they have on the body's function.
"For example, melanomas in the back passage might eventually affect the horse's ability to pass droppings.