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Editor,—Most of the reported cases of epithelial growth in the anterior chamber are related to cataract surgery and injuries.1-3 Epithelial invasion of the anterior chamber after perforating keratoplasty (PK) is a rare complication. Only a few authors report on epithelial cysts after PK,45 while the majority of the presented patients in the literature suffer from diffuse epithelial downgrowth.167 We present three patients with cystic epithelial growth in the anterior chamber 1–10 years after primary PK and histopathological findings after complete removal of the cyst.
All three patients were referred to our department with cystic epithelial growth into the anterior chamber. Primary PK was carried out elsewhere. Block excision and corneoscleral grafting were performed by one of us (GOHN) in all three patients. Technical aspects of block excision have been described in detail earlier.28-10
Patient 1 is a 31 year old man. He underwent PK on his right eye because of a keratoconus. Thirteen months later cystic epithelial growth in the anterior chamber was noted with increase in size. At the time of operation the cyst size was below two clock hours on the limbal circumference. Block excision (6.0/6.1 mm) was performed in toto. Histological specimen showed a epithelial cyst formed by non-keratinising epithelium with goblet cells. During the follow up period of 48 months no recurrence of epithelial growth was observed. Preoperative visual acuity at the time of block excision was 20/20, visual acuity at the last check was 14/20; preoperatively intraocular pressure (IOP) was unremarkable, and IOP at the last check was 15 mm Hg.
A 29 year old woman underwent PK on her right eye because of lattice corneal dystrophy. After 47 months a epithelial cyst was seen for the first time. Block excision (6.0/6.1 mm) of the cyst, which had increased in size (below three clock hours of the limbal circumference), was performed. The histological finding was a cystic epithelial growth by non-keratinising epithelium. Goblet cells were not observed in the specimen (Fig 1). Visual acuity at the time of surgery was 8/20; the last examination during the follow up period (13 months) revealed a visual acuity of 10/20, IOP was 19 mm Hg both preoperatively and postoperatively.
This was a 29 year old woman. She had undergone PK on the left eye 10 years earlier after herpes simplex keratitis. Cystic epithelial growth was noted 10 years after PK. Epithelial cyst (below three clock hours of the limbal circumference) was removed by block excision (7.5/7.6 mm) in toto. Histological examination revealed cystic epithelial growth by non-keratinising epithelium with goblet cells. Cystic epithelial ingrowth was removed in toto. Visual acuity at the time of surgery was 4/20, IOP was within normal limits. The last follow up (follow up time 7 months) revealed a visual acuity of 6/20, IOP was within normal range (18 mm Hg).
In all three patients the cyst was adjacent to the corneal surface, the iris, and the chamber angle structures.
Several other surgical methods have been described for treatment of epithelial ingrowth. Proposed methods are aspiration of the cyst, diathermy, cryocoagulation, YAG laser treatment of the cyst wall, or excision of the cyst itself. In our experience, surgical opening of the cyst tends to result in diffuse epithelial ingrowth and, consequently, the potential loss of the eye.12 Excision of the cyst itself on the other hand is not possible, because in all histological specimens obtained by block excision (up to 60 patients) the epithelial cyst covered the corneal surface, the chamber angle structure, the anterior surface of the ciliary body, and the iris surface.
The pathway for the epithelial ingrowth is uncertain; possible pathways are sutures, forceps and other surgical instruments, prolonged postoperative hypotony, and retardation of wound healing and wound dehiscence.
The interval between primary surgery and clinical appearance of epithelial ingrowth may vary from 1 week to 38 years.14-6 In our patients the symptom-free interval was 1–10 years. In cystic epithelial ingrowth increase in the cysts size seems to be limited by the corneal endothelial cell layer on the surface of the cyst (“Zagorski effect”).3
The purpose of every treatment of cystic epithelial growth should be the complete eradication of the invaded epithelium. Surgical opening of the cyst (for example, by laser application) is contraindicated, because this intervention may transform cystic epithelial ingrowth into a diffuse epithelial ingrowth, resulting in severe secondary glaucoma and eventually the loss of the eye. Reported rate of local recurrences (up to 14–100%) and following enucleations (up to 18–33%) in reported series are relatively high.2
In conclusion, cystic epithelial ingrowth after PK without previous ocular surgery or trauma is very rare. In our experience block excision and corneoscleral grafting28-10 are the treatment of choice if the cyst is not above five clock hours of the limbal circumference. This procedure leads to morphological and functional rehabilitation of the eye.