Superficial keratectomy and cryosurgery as therapy for limbal neoplasms in 13 horses

To determine the usefulness and clinical outcome of a combined procedure of superficial keratectomy and cryosurgery as a treatment for limbal neoplasms in horses.

Retrospective study.

Thirteen horses with 14 limbal tumors.

Medical records of all patients with limbal tumors, referred to the Department of Equine Sciences of Utrecht University between 1995 and 2002, were retrieved. Patient data were analyzed with respect to signalment, tumor surface area and histologic diagnosis. Surgery, performed under general anesthesia, included surgical debulking of the tumor followed by cryosurgery. Long-term follow-up information was obtained by re-evaluation in the clinic, by the referring veterinarian, and/or by telephone enquiry.

Therapy was successful in 9 out of 14 eyes after the first attempt (64%); one eye needed retreatment (7%), and four eyes were eventually enucleated (29%). The mean follow-up period was 4.8 years. The initial surface area of the tumor significantly influenced outcome (P < 0.01). Squamous cell carcinoma was the most predominant tumor type (79%). Haflinger horses accounted for 69% of the cases whereas their occurrence in the overall hospital population is approximately 5%.

The described technique of superficial keratectomy and cryosurgery is a simple procedure for the treatment of limbal tumors in equine patients that does not require sophisticated equipment. Nor is it tampered by legal restriction, and appears to be effective in tumors with a small surface area (< 2 cm2). Haflinger horses seem to be predisposed for the development of ocular squamous cell carcinoma.