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Ask Dr Emily Weaver Your Own Question
Dr Emily Weaver
Dr Emily Weaver, Horse Veterinarian
Category: Horse Veterinary
Satisfied Customers: 34
Experience:  Equine Veterinarian with over 11 years experience in ambulatory practice
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My horse has a spot in her eye. Is it most likely melanoma

Customer Question

My horse has a spot in her eye. Is it most likely melanoma or sclera like melanocytosis?
Submitted: 8 months ago.
Category: Horse Veterinary
Customer: replied 8 months ago.
Here is the picture.
Expert:  Dr Emily Weaver replied 8 months ago.

Hello, this is Dr Weaver, I am an experienced equine vet and I just took a look at your picture, and if I am seeing correctly, it looks like a pink mass at the horse's limbus (where the cornea meets the white part of the eye), I have seen masses like this before, and this definitely looks like Squamous Cell Carcinoma (SCC) of the limbus. SCC is an aggressive type of cancer, and best thing you can do is get your horse seen by a veterinary ophthalmologist, they will recommend surgery and a course of chemotherapy (usually topically, or they can inject the drugs). If treated early and aggressively, you can save the eye, if left untreated she can possibly lose the eye.

I hope this helps, please let me know if you have any further questions or concerns,


Dr Weaver

Customer: replied 8 months ago.
Actually I am talking about the black / gray blue spots. (I was told the pink mass is scar tissue)
Customer: replied 8 months ago.
The black spots just appeared
Customer: replied 8 months ago.
This summer her eye had this problem.
Customer: replied 8 months ago.
The vet cleared it to this with a steroid.
Customer: replied 8 months ago.
Now this black spot appeared.
Expert:  Dr Emily Weaver replied 8 months ago.

Ok, thanks for the extra pics, these help me see things more clearly, just to make sure I am oriented correctly, this area is at the outside edge of her eye right? Not on the third eyelid?

The pink area in the first shot is suspicious of SCC (the one from over the summer) but then it looks better in the next one after treatment, it doesn't look as raised as before, so less likely to be SCC.

The black spots you are seeing are likely scleral melanocytosis, which is generally harmless. A lot of horses get black pigmented areas on the sclera like that and it is considered within the realm of normal so I would just keep an eye on it. If that area starts to get raised up more, becomes darker pink/red and raised again, then have your vet check it out.

Customer: replied 8 months ago.
They just disappeared. Her eye is red now and the black spots are gone. Could she be getting something in her eye? What would cause the temporary black spots? A chemical?
Expert:  Dr Emily Weaver replied 8 months ago.

The pictures showing the black spots, while not seen in all horses, are considered a normal variant, and shouldn't cause any trouble. Now that her eye is red, my guess is the spots haven't truly disappeared, they are just being overshadowed by the redness, which is conjunctivitis. The conjunctiva is highly vascular and when it is inflamed, the vascularization of that area can increase rapidly. Recurrent conjunctivitis is usually caused by allergies, and a steroid ointment should help with that. Make sure her eye itself is not painful before putting any kind of steroidal ointment in the eye. A painful eye always warrants a vet visit. If the red area gets worse or becomes raised/bumpy, that would be concerning for SCC.

Expert:  Dr Emily Weaver replied 8 months ago.

Hi, just checking in to see how your mare's eye is doing.

My goal is to provide you with excellent service, if you are satisfied, please rate me. If you have further questions on this topic, please feel free to message me here, thank you,

Dr Weaver