British Journal of Ophthalmology, 1978, 62, 155-158

Intracorneal and sclerocorneal cystsG. M. LIAKOSFrom the Corneoplastic U,iit, Qu(een Victoria Hospital, East Grinstead, Slussex

SUMMARY Two cases of corneal cysts are reported, one sclerocorneal and the other intracorneal.The two conditions differ in pathogenesis, appearance, course, and management.

The presence of a corneal cyst is a rare clinical con-dition. Only a few cases have been reported in theliterature. Most of the corneal cysts have a scleralcomponent from where they actually originate.These are described as congenital and progressive incourse, although scleral cysts without corneal in-volvement have been reported. A small number ofcysts are strictly corneal and of presumed con-genital origin. Nevertheless, they can be a product oflocal trauma or follow ocular surgery.There are differences in appearance, pathogenesis,

treatment, and prognosis between the intracornealand sclerocorneal variants of this cystic condition,and these are demonstrated by the following reportof two such cases.

Case reports

CASE 1A White baby girl was first taken to the localophthalmologist at the age of 10 months because her

Address for reprints: Dr G. M. Liakos, Southampton EyeHospital, Wilton Avenue, Southampton S09 4XW

mother had noticed a small spot in the right eye. Thiswas diagnosed as a conjunctival cyst, and no specifictreatment other than simple observation was under-taken. The cyst gradually increased in size, and whenat the age of 21 years the patient was referred to thisunit an examination under anaesthetic was per-formed with the following findings.A small scleral cyst was present at the supero-

nasal quadrant beginning at 2 mm from the limbusand invading the cornea for a further 2 mm atthe level of mid-stroma. The remaining corneawas normal, but faint scarring at the level ofBowman's membrane surrounded the corneal ex-tension. Gonioscopy revealed a normal angle, andexamination of the rest of the eye showed noabnormality.No surgery was performed until 13 months later,

when the cyst was much larger, involving the nasaledge of the pupillary axis, reducing the visual acuityto 6/36. In addition cell debris simulating a hypopyonlevel could be seen occupying the bottom of thecystic cavity (Fig. 1). At that stage aspiration wasperformed, and the aspirate was identified histo-

Fig. 1 Sclerocorneal cyst. Notethe scleral origin of the cyst(black arrow) and the cell debrissimulating a hypopyon level inthe cavity of the corneal eAtension(white arrow)

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logically as containing 'numerous degenerate epi- visual acuity remains unchanged, and because of thisthelial cells' (Fig. 2). a lamellar graft is planned for the near future.

During the next 6 months the cyst refilled and in-creased further in size. Thus, the anterior wall wasremoved surgically to the largest possible extent andthe remaining portion was cauterised. The nasal partof the cornea was left, without graft, using the epi-thelial lining of the cyst as the covering layer.Histological examination confirmed the diagnosis ofinclusion cyst resulting from congenital sequestra-tion of epithelium (Fig. 3).

Four months later the cyst has not re-formed andthe cornea has healed with a thin, even scar. The

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Fig. 2 Histological appear-anceof the cyst aspirate. Multipleepithelial cells can be seen, the -clarker ones representing thebetter preserved cells. H and E.x 125

CASE 2A healthy White boy 10 years old presented to theclinic because his mother had noticed a spot on hisright eye. There was some vague history of localinjury some years ago but otherwise nothing signi-ficant. There was no family history of eye diseaseapart from a grandfather who apparently was blindfrom retinal disease.

Examination showed the visual acuity 6/6 in eacheye, with no significant refractive error. On the right

Fig. 3 Histology of the anteriorwall of the cyst. Squamousepithelium cover-s both sides ofthe wall. H and E. x 50

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Intracorneal and sclerocorneal cysts

side there was a limbal intracorneal cystic lesion inthe superonasal quadrant (Fig. 4). There were noblood vessels, but a nebulous opacity outlining thelesion was present. The anterior wall of the cyst wasformed by epithelial cells and perhaps Bowman'smembrane. The posterior wall was formed by a thinlayer of Descemet's membrane in the centre of whichthere was a pinpoint circular gap covered only withendothelial cells (Fig. 5). The adjacent sclera wasnormal, and gonioscopy revealed a wide open angle.The rest of the right eye and the entire left eye werenormal. This cystic lesion has been observed forover 6 years, and no change has occurred at all.

Discussion

The origin of the sclerocorneal cyst is clear from thehistological picture of the aspirate and the cyst wall.The presence of epithelial cells points towards asequestration of conjunctival epithelium, and this isin complete agreement with most of the previouslydescribed cases (Fox, 1928; Huber, 1930; Lepri, 1947;Bischler, 1947; de Ferrari, 1950; Mandras, 1951). Analternative theory was put forward by Wernicke (1908)when, in describing a case, he suggested that the cystwas an extension of the anterior chamber. Custodis(1932) demonstrated that such cases were out-

;$.;>aX ~Fig. 4 Slit-lamp appearance ofintracorneal cyst. Note absence of

.... . sc/era involvement

Fig. 5 Higher magnificationreveals a pinpoint gap in theposterior wall of the cyst(large arrow), covered only byendotheliimn (small arrow)

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G. M. Liakos

growths of the canal of Schlemm, and Vrolijk (1941)favoured a similar theory. This was not the patho-genesis in the present case, because no continuationwith the anterior chamber was present and gonios-copy showed a normal angle. Babel and Avanza(1966), reviewing 18 reported cases, stated that theyusually become evident at the age of 5 or 6 years. Thepresent case is rather unusual in becoming apparentat the age of 10 months, although the youngestpatient reported was that of Custodis (5 months).The fact that simple aspiration was followed by no

significant improvement underlines the importanceof excising the anterior wall if a more permanentcure is desirable. As the course is progressive, failureto treat will impair the sight by extending over thepupillary area. In that case corneal grafting may benecessary in order to restore maximum vision.

Intracorneal cysts without scleral involvement arevery rare. Appia (1853) was the first to describe sucha case, and authors of the majority of the approxi-mately 30 cases reported since accept a congenitalorigin, analogous to that of the sclerocorneal cysts.However, some authors have suggested a traumaticorigin, for example Ruedemann (1956) reporting acase associated with a foreign body, and Reed andDohlman (1971) reporting 8 cases following eithercorneal surgery or undetected injury.The traumatic theory is more attractive, and,

although in many cases no history of injury is found,a trivial, undetected accident is sufficient to force anumber of epithelial cells into the stroma, wherethey become isolated owing to closure of the surfacewound. This theory is supported further by thenormal appearance of the sclera and the anteriorchamber, the clinical similarity with the traumaticcysts, and the non-progressive course of the con-dition.

The latter is significant in connection with themanagement ot the intracorneal cysts. On diag-nosing such a condition a conservative approachshould be adopted, and only in the unlikely event ofextension of the cyst should surgery be undertaken.

I thank Miss Smith for secretarial assistance and thePhotographic Department of Queen Victoria Hos-pital for the illustrations. Mr T. A. Casey and MrA. Werb offered great help and encouragement.

References

Appia, A. (1853). Archives of Ophthalmology (cited byBischler).

Babel, J., and Avanza, C. (1966). Les kystes sclerocorneenscong6nitaux et leur 6volution. Societe Suisse d' Ophtalmo-logie, 152, 352.

Bischler, V. (1947). Un cas de kyste congenital scleracorneen.Ophthalmologica, 114, 371-376.

Custodis, E. (1932). Uber Skleralcysten. Albrecht vonGraefes Archiv fur Ophthalmologie, 128, 112-118.

de Ferrari, G. (1950). Un raro caso di cisti congenita sclera-corneale. Bolletino d'Occulistica, 29, 223-233.

Fox, L. W. (1928). Bilateral cysts of the cornea. BritishJournal of Ophthalmology, 12, 249-254.

Huber, W. A. (1930). Cystic degeneration of cornea andsclera. American Journal of Ophthalmology, 13, 424-431.

Lepri, G. (1947). Ciste epitheliale sclerocorneale di originecongenita associata a malformagioni congeniti del fundus.Archivio di Ottalmologia, 51, 43-105.

Mandras, G. (1951). Epithelial cyst of the cornea. Tran-sactions of Greek Ophthalmological Societies, 19, 159.

Reed, J. W., and Dohlman, C. H. (1971). Corneal cysts.Archives of Ophthalmology, 86, 648-652.

Ruedemann, A. D. (1956). A corneoscleral epithelial in-clusion cyst. American Journal of Ophthalmology, 41,316-317.

Vrolijk, M. (1941). Corneoscleral cysts. Acta Ophthalmo-logica, 19, 44-51.

Wernicke, P. (1908). Cysten der lederhaut. Archiv furAugenheilkunde, 59, 23-28.

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