Peer-reviewed veterinary case report
Corneal Squamous Cell Carcinoma Arising From a Conjunctival Graft Scar in a Horse.
- Journal:
- Veterinary ophthalmology
- Year:
- 2026
- Authors:
- du Preez, Surita et al.
- Affiliation:
- School of Animal and Veterinary Sciences · Australia
- Species:
- horse
Plain-English summary
A case was reported about an 18-year-old Thoroughbred gelding that developed a type of skin cancer called corneal squamous cell carcinoma (SCC) in the left eye, specifically from a scar left by a previous eye surgery done 34 months earlier. The horse showed signs of the cancer through a growing, raised mass on the cornea that had a pink color and some pigmentation. To diagnose the issue, the veterinarians performed a thorough eye exam and took a small tissue sample for testing, which confirmed the cancer. They treated the horse with a special laser procedure and chemotherapy, and this treatment successfully removed the cancer. The horse was later euthanized for other health reasons four years later, and there were no signs of the cancer coming back.
Abstract
OBJECTIVE: To describe the case details of an equine corneal squamous cell carcinoma (SCC) arising from the central scar of a previous conjunctival pedicle graft. ANIMAL STUDIED: An 18-year-old Thoroughbred gelding, showing a progressive increase in diameter, depth, opacity, and pigmentation of a conjunctival pedicle graft scar of the left eye, 34 months after surgery. PROCEDURE(S): Complete ophthalmic examination, standard histologic and immunohistochemical evaluation of an incisional biopsy to formulate a definitive diagnosis. Carbon dioxide (CO) laser photoablation combined with topical mitomycin C treatment. RESULTS: Initial examination with slit-lamp biomicroscopic examination revealed a raised, pale pink and peripherally pigmented, ovoid corneal mass (25 × 20 mm, raised 5 mm) with a smooth to cobblestone contour, paraxial ventral at 6 o'clock of the left eye. Corneal neovascularization extended from the ventral limbus to the graft scar. The remaining ophthalmic examination was unremarkable. Histologic and immunohistochemical evaluation of an incisional biopsy were supportive of a diagnosis of corneal SCC. Two rounds of COlaser photoablation, 10 weeks apart, combined with topical mitomycin C chemotherapy, without surgical debulking, was successful in resolving the neoplastic lesion. The horse was euthanized 4 years later for unrelated reasons, with no evidence of SCC recurrence grossly or histologically. CONCLUSION: To the authors' knowledge, this is the first report in a horse of a SCC developing at the site of corneal scarring after a conjunctival pedicle graft.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/41090548/