Stand Up to Cancer: Standing Surgery on a Squamous Cell Carcinoma

I saw a pretty awesome case yesterday. I was called for an eye “emergency” (the horse has had the problem for several months, but now that they want it treated it’s suddenly an emergency). I squeezed them into my schedule for the day, not knowing what I was going to see, and when I arrived I saw this:

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(Well, that’s not EXACTLY what I saw, these pictures were taken after I cleaned off the copious amounts of what I like to call “schmoo” – mucopurulent discharge, or in lay terms, pus.)

Due to the history of an ongoing, worsening problem, the signalment of the horse (Paint, 16 years old), and the appearance and location of the lesion (cauliflower-like, on the third eyelid, lots of schmoo), I thought it was highly likely that this horse had cancer, specifically squamous cell carcinoma, on its third eyelid. When I was a fourth year vet student I removed a third eyelid on a Paint horse with a much less extensive lesion. Based on that experience I felt confident that I could remove the eyelid successfully, although due to the proliferative nature of his lesion I was concerned that it would be difficult to get clean margins.

The owner was excited to try the surgery, so I prepped the horse and we got going.

First, the horse was fairly heavily sedated, slightly more than I would give a dental float. I placed his head on a stand for balance and stability, and then, using Lidocaine, blocked the auriculopalpebral and supraorbital nerves, effectively stopping motor and sensory function to the eyelids.

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I also attempted to block the mass and third eyelid, just in case the other two blocks were not sufficient. Unfortunately due to the vascularity of the mass (again suggesting tumor, as they tend to have angiogenic properties) I think all I succeeded in doing was causing a lot of bleeding. He didn’t flinch when I put the needle into the third eyelid though, so I was pretty sure I had complete local analgesia.

Due to the size and extensive nature of the mass, I had to take it out in sections. I used my large hemostats to clamp behind the bulk of the mass, crushing the blood vessels and allowing me to cut the mass free with minimal bleeding. After removing the mass I was able to expose the third eyelid, which I clamped again at the base, crushing the blood vessels and allowing me to remove it in its entirety. I also trimmed a small section of conjunctiva, as the tumor was invading some of the surrounding tissue. It is because of this that I am unsure that we were able to get a clean margin.

Here are our post-op pictures, keeping in mind his eyelid is still numb:

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We put him on a short course of antibiotics to prevent infection, anti-inflammatories to help with post-operative swelling, and ophthalmic antibiotics since we were working very close to his eye, just to prevent an ulcer if one of the instruments happened to scratch his cornea during the procedure. We also submitted the mass for histopathology to find out a definitive diagnosis. This will tell us if the mass is likely to recur and if we should begin treatment with a chemotherapeutic agent.

That was definitely the most exciting thing I’ve seen and done this week. I’ll leave you with a picture I snapped in a fancypants barn this morning:

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Antler chandelier! Cool right?

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