For any grey horse owner, melanomas are part of the package, with 80% of grey horses over the age of 15 likely to encounter one or more in their lifetime. However, melanomas can develop on any horse, so every horse owner should understand more about them.
While skin cancer is much less prevalent in horses than humans, common skin cancers, like melanomas, can pose a health risk and cause your horse discomfort. Thankfully, they’re often benign, but that doesn’t mean they should be ignored.
What is a Melanoma?
A type of tumour, melanomas are an uncontrolled growth of cells that are usually malignant. Generally brown, grey or black in colour, they most often appear on the underside of the tail, perineal and peri-anal regions.
However, they’ve also been found on the penis and sheath, ears, eyes, head and jugular region. When they first appear, melanomas are subcutaneous – covered by skin – but, over time, they can become ulcerated or infected and require treatment.
Management and Treatment
Any presence of melanomas should be watched carefully. Even benign, slow-growing melanomas have the potential to develop into a malignant growth, so you must routinely check your horse for any changes in size or appearance, or new growths.
If found in certain areas, any melanoma – benign or malignant – can interfere with your horse’s comfort, particularly if located in the bridle or saddle areas. Some malignant melanomas can also limit your horse’s excretory functions, as well as breeding and foaling if around the peri-anal regions.
Sometimes melanomas are removed by surgery. For those nuisance benign melanomas, this is often the best method. However, freezing with liquid nitrogen, chemotherapy and radiation are often used in partnership with surgery in malignant cases.