Evisceration of a blind eye with multiple previous operations
Evisceration specimens usually include the cornea (with a scleral rim) as well as the intraocular content. In contrast to enucleations, the tissue is disrupted by the surgery. This can make it difficult to recognise anatomic structures, especially as there is often scarring and disorganisation due to the original pathology. In chronic disease, it is not always possible to give a specific diagnosis. The points I make sure to comment on (even in their absence) are whether or not there is malignancy, and whether or not there is sympathetic endophthalmitis. The latter is a rare but potentially catastrophic condition that can affect the patient’s other eye.
The cornea is distorted by scarring. There is band keratopathy (calcification of Bowman’s layer) and superficial vascularisation, along with a sprinkling of inflammatory cells. On the posterior surface, there is a cellular layer which is more prominent than the usual endothelium. In a couple of places, it appears multilayered. In this context, I have a strong suspicion of epithelial downgrowth.
In the annotated image, I’ve highlighted the band keratopathy in blue. Arrows mark the blood vessels. The abnormal posterior cellular layer is marked in green, with a green asterisk marking the multilayering.
This is a higher power view of the cornea, stained with PAS. There is a subtle linear scar through the stroma which interrupts Descemet’s membrane. This indicates prior (full-thickness) perforation of the cornea. Posteriorly to Descemet’s membrane is a sheet of fibroconnective tissue ie retrocorneal fibrosis. Additionally, the surface epithelium includes a goblet cell which contains PAS-positive mucin. Normal corneal epithelium does not contain goblet cells, and this is indicative of conjunctivalisation.
In the annotated image, I’ve marked the scar with a green line, the break in Descemet’s membrane with an arrow, and the goblet cell with an asterisk.
This is a disorganised mass of the intraocular contents. It includes iris, ciliary body, vitreous, retina and choroid. There are empty spaces which may have contained an intraocular lens although I’m not sure of this.
In the annotated image, I’ve indicated the iris (i), ciliary body (cb) and vitreous. The vitreous includes (abnormally) blood vessels and a rather solid matrix, which I’d refer to as proliferative vitreoretinopathy. I’ve indicated the disorganised retina with green hatching and the choroid with yellow hatching. There’s also a very small fragment of lens cortex, which I’ve marked with an asterisk.
This is a higher power view of the above image, including iris and ciliary processes. A sheet of multilayered epithelium coats both the anterior and posterior iris surface. Additionally, it continues into the vitreous cavity (bottom right) to form a cyst.
In the annotated image, I’ve marked the extent of the epithelium with a green line.
This case demonstrates extensive epithelial downgrowth. This occurs after the eye is breached: whether through injury or (more rarely) surgery. Ocular surface-type epithelium gains access to the inside of the eye where it proliferates across the posterior cornea. It may spread around the angle (causing blockage and glaucoma) and over the more posterior structures. I’ve seen occasional cases where the epithelium grows across the retina! Fortunately, with improvements in elective surgical techniques and post-trauma repair, epithelial downgrowth is much rarer than it used to be.
There isn’t much literature about the histopathology of epithelial downgrowth, probably because the mechanism is straightforward. Here are a couple of open access (free to read) articles.
Epithelial downgrowth: a 30-year clinicopathological review by Weiner et al is a review of 124 patients treated over a 30-year period.
Traumatic Epithelial Downgrowth After Radial Keratotomy by Nemi et al. This case report is quite interesting since radial keratotomy (an early refractive surgery technique) shouldn’t penetrate into the eye.