Location: Like scars, tumors can appear just about anywhere on your horse’s body. If you have a gray horse, pay especially close attention to his rectum, tail, and sheath area, as this is where melanomas often appear.
What it is: A tumor is a mass of cancer cells. There are a wide variety of different equine skin tumors, including melanomas, squamous cell carcinomas, cutaneous (skin) lymphosarcomas, and sarcoid tumors. The only way to accurately identify a tumor is for your vet to collect a sample (either through a needle or by cutting out a portion of the mass) and submitting it to a laboratory for evaluation under a microscope.
Look and feel: Tumors can have a variety of different appearances, and can therefore be hard to describe.
Should you worry: If you find a lump or bump on your horse that’s new and doesn’t fit any of the other common bump descriptions, watch it carefully—especially if it seems to be growing. It never hurts to schedule a visit from your vet, who can advise if additional testing is necessary.