Background: Intrastromal corneal cysts are uncommon lesions caused by the implantation of corneal epithelial cells in the stroma, and their subsequent intrastromal proliferation, which has often been secondary to trauma. Lamellar keratectomy has been the chosen treatment and diagnosis has been confirmed by histopathology. In this report, we describe a case of corneal epithelial inclusion cyst in a dog that was successfully treated with lamellar keratectomy. Case: A 10 year old Yorkshire Terrier dog was referred to the Ophthalmology Section of the Veterinary Clinics Hospital of the Federal University of Rio Grande do Sul (UFRGS), presenting an abnormal appearance in the left cornea. The ophthalmic examination revealed a white and elevated mass, measuring approximately 3 mm in the left cornea. Thus, a superficial keratectomy was performed by utilizing an angled ophthalmic disc knife, under general anesthesia, and an operating microscope. In addition, a third eyelid flap was performed to protect the cornea. The postoperative treatment involved broad-spectrum antibiotic containing tobramycin 0.3%, and a non-steroidal anti-inflammatory solution of sodium diclofenac 0.1%, administered six times a day for two weeks. In addition, atropine sulphate 1% was applied once a day for five days. After three weeks of follow-up, the third eyelid flap was removed, and there was no evidence of corneal ulcer. After two years, no recurrence has been observed. Discussion: Studies have indicated that the epithelial inclusion cyst is congenital or traumatic. In this case, the dog had a history of previous corneal ulceration occurring at the same site of the cyst. Regarding clinical signs, studies have reported that a corneal cyst does not cause ocular discomfort, although excessive tearing and blepharospasm have been reported. At the moment of examination, the dog presented ocular discharge, discomfort and conjunctival congestion. Normally, a definitive diagnosis is made after cytology or histopathology; however, the diagnosis of corneal cyst in this dog was confirmed through the histopathology of the mass after surgical excision. Keratectomy has been the chosen treatment to remove cysts. Although the recurrence of a cyst is not expected, it has been described fifteen months after the first keratectomy. The most likely explanation for this recurrence could be an incomplete and inadequate surgical excision of the original cyst. In this study, keratectomy was carried out and the entire cyst, along with its sac, was then removed. It is important to remove the cyst rather than draining it, once if the cyst and sac-cover are not totally removed, there is a great possibility of the cyst growing back and getting larger. After keratectomy pedicle conjunctiva graft, third eyelid flap, tissue adhesive, and therapeutic contact lens can be utilized. In this case, third eyelid flap was utilized after keratectomy. The concomitant medical therapy was realized with the topical utilization of broad-spectrum antibiotics in order to prevent bacterial contamination. In addition, the topical atropine sulphate 1% was utilized to dilate the pupil, helping to decrease pain associated with secondary uveitis; non-steroidal anti-inflammatory drug was utilized to control the inflammation. Lastly, the third eyelid flap suture was removed three weeks after surgery, and there was no evidence of corneal ulcer; periodic evaluations were realized every three months and there were no signs of recurrence after one year. In the present case, lamellar keratectomy associated with third eyelid flap was effective in the treatment of corneal epithelial inclusion cyst in a dog.
