Clinical and diagnostic evaluation of intraocular expulsion of a corneal epithelial inclusion cyst in a dog.

An 8-year-old spayed female mixed-breed dog was presented for evaluation of an axial, raised, vascularized, lightly pigmented 3 mm diameter corneal lesion affecting the left eye (OS) that was present since adoption three years prior to presentation. The presumed cyst ruptured into the anterior chamber 5 months following initial presentation with progressive extrusion of intralesional contents into the anterior chamber. High-frequency ultrasound and in vivo confocal microscopy revealed minimal normal stroma posterior to the corneal lesion. Due to the lack of stroma, a deep anterior lamellar keratoplasty (DALK) was attempted using the viscodissection technique. While separating the stroma from Descemet's membrane, a tear in the membrane was observed, and the procedure was converted to a penetrating keratoplasty (PK). The mass was excised en bloc, and a frozen corneal allograft and conjunctival pedicle graft were utilized to restore corneal thickness. The extruded material was irrigated out of the anterior chamber and submitted for culture and cytology. There was no growth on aerobic, anaerobic, or fungal cultures, and cytology revealed mixed neutrophilic and macrophagic inflammation with keratinizing squamous epithelium. Histopathology identified the mass to be a corneal epithelial inclusion cyst lined with well-differentiated stratified squamous epithelium. The dog is doing well 10 months post-operatively with no signs of recurrence along with good comfort and vision.