Ocular Lymphangiosarcoma in a Horse

An 18-year-old Percheron cross mare presented to the Cummings School of Veterinary Medicine at Tufts University for evaluation of progressive corneal clouding and conjunctival swelling involving the right eye. Ophthalmic examination demonstrated widespread infiltrative opacification and vascularization of the right cornea, most extensive ventrally and extending dorsolaterally. The palpebral conjunctiva was hyperemic with moderate chemosis and demonstrated follicular proliferation ventrally. The bulbar and palpebral conjunctiva of the nictitating membrane appeared grossly thickened. A mild amount of fibrin was noted within the anterior chamber. The horse was placed under general anesthesia, and the right eye was enucleated using a transpalpebral approach. Light microscopic examination of the ocular tissues demonstrated a neoplasm consistent with lymphangiosarcoma, which was believed to have originated from the bulbar conjunctiva, with subsequent invasion into the neighboring cornea, sclera, and periocular muscles. Follow-up conversations with the owner and referring veterinarian revealed that the horse was doing well 9 months postoperatively. Lymphangiosarcoma is an extremely rare neoplasm that originates from the lymphatic endothelium. Lymphangiosarcoma is typically considered to be an aggressive, malignant tumor and is associated with high metastatic and mortality rates in both physician-based as well as veterinary medicine. This is the first case report of lymphangiosarcoma arising from the bulbar conjunctiva and subsequently affecting the cornea, sclera, and periocular muscles in any species. This case also describes a survival time longer than that reported for any equine with this neoplasm.