Treatment of Limbal Melanocytoma with Full Excision and a Fresh Homologous Corneoscleral Graft in a Dog

Background: Limbal melanoma has been diagnosed in dogs and due to progression may cause vision loss and eyeball removal. Definitive diagnosis is made through histopathological examination. Therapeutic options include full thickness resection and repair by homologous corneal tissue, synthetic graft material, and enucleation. In this report, we describe a case of limbal melanocitoma in a dog that has been treated successfully with fresh homologous corneoscleral graft.Case: A 5-year-old female Labrador was referred to the Ophthalmology Veterinary Section of the Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil, with a history of a pigmented mass located on the left eye. Ophthalmic examination revealed a pigmented mass located at the left temporal limbus with corneal involvement. Surgical excision followed by reconstruction using fresh homologous corneoscleral was recommended. The patient was premedicated with acepromazine (0.05 mg/kg, IM) and meperidine (20 mg/kg, IM). Anaesthesia was induced with propofol (10 mg/kg, IV) and maintained with isoflurane. Atracurium (0.2 mg/kg, IV) was administered to maintain a central eye position. The mass and a free margin were removed by full-thickness corneoscleral resection. A corneoscleral graft was harvested from a dogthat had been euthanised for reasons unrelated to this study and sutured with 9-0 polyglactin 910 using a simple interrupted pattern. The mass was immediately fixed in 10% neutral buffered formalin and submitted for histological sectioning and routine staining. Based on the histopathological analysis it was confirmed limbal melanocytoma. Postoperative treatment consisted of topical administration of 0.3% flurbiprofen every 6 h for 15 days, and a combination of topical ciprofloxacin/dexamethasone eye drops every 6 h for 30 days. Systemic carprofen (4 mg/kg per day, VO) was prescribed for 10 days. Topical tropicamide was used twice daily for 1 week. Cyclosporin 0.2% eye drops were applied twice daily for 2 months. Examination of the left eye two months after surgery revealed decreased corneal vascularization, and the results of pupillary light response and vision testing were normal. The values of intraocular pressure remained normal in all postoperativeevaluations. The patient was followed for 36 months postoperatively, during which time there was no recurrence.Discussion: Limbal melanomas are the most common ocular melanomas in dogs. Most of them develop slowly and are located closely t