Intrascleral cysts are rare diseases in childhood and have an uncertain etiology. Because most intrascleral cysts have been reported to develop after ocular trauma or surgery,1,2 the introduction of epithelial cells and subsequent proliferation of the cells are considered to lead to cyst formation. However, there are cases where cysts are present at birth and without a history of trauma or surgery.3–7 We present a primary case of intrascleral cyst with corneal extension that progressively enlarged and was treated by surgical excision and allogeneic sclerolimbal graft.
A 3-year-old boy was referred for a protruding grayish mass in the right eye that was noticed by his parents 2 months ago. There was no complaint of ocular discomfort. The patient was born spontaneously without complication after full-term pregnancy. There was no history of trauma or surgery. Family history was unremarkable.
On examination, visual acuity was 20/20 in both eyes and intraocular pressure was 14 mm Hg in both eyes. Mild ptosis was observed in the right upper eyelid. The marginal reflex distance (MRD) was 2 mm in the right eye and 4 mm in the left eye. Slit-lamp biomicroscopy revealed a large cystic mass with prominent scleromalacia at the superonasal limbal sclera in the right eye (Figures 1A–1B). The intracorneal cyst was present at the nasal periphery. There were no signs of inflammation, such as conjunctival or scleral injection and anterior chamber reaction. The anterior chamber depth in the periphery was deep in all quadrants. The fundus was normal, and there was no abnormal finding on B-scan ultrasonography. The patient was examined by a rheumatologist for systemic and rheumatologic disorders causing scleromalacia, but no abnormality was found.
(A and B) Anterior segment photography at presentation. Scleral cystic mass and scleromalacia were observed at the superonasal limbal sclera. Intracorneal cyst with fluid collection was also present at the nasal cornea with an intrastromal connecting tract between scleral and corneal cysts (white arrow). (C and D) Anterior segment photography 9 months later. Both scleral and intracorneal cysts markedly enlarged.
The patient was observed every 2 months. The size of the scleral and intracorneal cysts was remarkably increased over the next 9 months to the point that the involvement of the visual axis was threatened (Figures 1C–1D). The ptosis progressed to MRD 0 mm and visual acuity decreased to 20/30 in the right eye. Hence, surgical removal of the cyst was recommended.
At surgery, the conjunctiva overlying the scleral mass was dissected smoothly without adhesion. The scleral cyst content was aspirated with a 27-gauge needle and examined by cytology. Then, the anterior wall of the scleral cyst measuring approximately 7 (vertical) × 5 (horizontal) mm was excised (Figure 2A) and sent for pathology evaluation. After drainage and removal of the cyst, it was evident that the location of the scleral cyst was intrastromal at the limbus and the underlying scleral bed was thin (Figure 2B). The intrascleral cyst extended to the cornea through an intrastromal tract, generating an intracorneal cyst. There was no communication between the cyst and anterior chamber. The corneal cystic content was spontaneously drained when the scleral cyst wall was excised. The intracorneal cavity was irrigated gently with balanced salt solution through the connecting tract for 5 minutes. The scleral bed was also irrigated with balanced salt solution and brushed with Weck-Cel sponges to remove remnant epithelial cells. The sclerolimbal graft from an allogeneic donor was put in place to fill the scleral defect and secured to the adjacent sclera and limbus with 8-0 polyglactin and 10-0 nylon interrupted sutures, respectively. The conjunctiva was closed to cover the graft.
(A and B) Anterior segment photography during surgery. (A) After excision of the anterior wall of the scleral cyst, (B) the underlying scleral bed was thin. (C) Photomicrograph of an excised cystic wall showed a benign cystic lesion lined by non-keratinizing squamous epithelium with stromal edematous change (hematoxylin–eosin stain, original magnification ×100).
Cytologic examination of serous aspirates demonstrated the presence of non-malignant, inflammatory cells containing a few lymphocytes, monocytes, and polymorphonuclear leukocytes. Histologic examination of the excised tissues revealed that the anterior cyst wall was a benign cystic lesion lined by non-keratinizing squamous epithelium (Figure 2C).
After surgery, the graft was well adapted to the surrounding tissue. Mild corneal stromal opacity was observed in the affected area right after surgery, but gradually disappeared. The cyst did not recur in either the sclera or cornea during 12 months of follow-up (Figure 3). The cornea remained clear and ptosis improved. The best corrected visual acuity was 20/25 in the right eye with a refraction of +3.50 −5.00 × 40, whereas the visual acuity in the left eye was 20/20 with +0.25 diopters sphere.
(A and B) Anterior segment photography 9 months postoperatively. No recurrence of cysts occurred, and the cornea regained clarity.
Intrastromal cysts of the cornea and sclera are rare in childhood. Most cases have been reported to occur after ophthalmic trauma or surgery,1,2 but there are reports of primary cases without a history of trauma or surgery, indicating the developmental origin of the disease.3–7
The common observation made with primary corneoscleral cysts is that they begin as an intrascleral cyst at the limbus and progressively expand to involve the corneal stroma in later years.3,4,6 In our patient, the scleral cyst remarkably enlarged in both height and diameter over 9 months and dissected further into the corneal stroma, leading to a large intracorneal cyst. Based on this observation, management of the scleral cyst at an early stage might be beneficial to prevent the disease progression. Also, (although we did not perform it in our patient) anterior segment imaging such as ultrasound biomicroscopy might be beneficial for diagnosis or follow-up of a lesion because it can provide information on the deep scleral lesion or ciliary body involvement.
We performed surgical excision of the anterior wall of the scleral cyst without surgical or chemical intervention to the corneal part due to the concern of corneal scarring. After surgery, the cornea was well healed without fluid recollection and completely recovered clarity. Therefore, it is possible that intracorneal cysts originate from intrascleral cysts and the removal of intrascleral cysts is important to treat both scleral and corneal cysts. Consistent with this, there are reports that recurrences occurred when only the corneal part of the cyst was drained or the epithelial cells lining the scleral cyst were not thoroughly removed.1,8 As in our case, several reports showed no recurrence of sclerocorneal cysts that were treated by the anterior scleral wall excision without the use of chemical cauterization.3,5,7,9 In these cases, tectonic grafting with corneal lamella, preserved sclera, or fascia lata was necessary to reduce the risk of staphyloma formation.3,5,7,9 Although we performed a tectonic sclerolimbal allograft to fill the scleral defect, a high degree of astigmatism developed in our patient, presumably due to the large size of the excised limbal scleral area. This observation reemphasizes the importance of early management of intrascleral cysts.
- Reed JW, Dohlman CH. Corneal cysts, a report of eight cases. Arch Ophthalmol. 1971;86:648–652. doi:10.1001/archopht.1971.01000010650007 [CrossRef]
- Bloomfield SE, Jakobiec FA, Iwamoto T. Traumatic intrastromal corneal cyst. Ophthalmology. 1980;87:951–955. doi:10.1016/S0161-6420(80)35141-5 [CrossRef]
- Mahmood MA, Awad A. Congenital sclerocorneal epithelial cyst. Am J Ophthalmol. 1998;126:740–741. doi:10.1016/S0002-9394(98)00128-7 [CrossRef]
- Rao SK, Fogla R, Bswas J, Padmanabhan P. Corneoscleral epithelial cysts: evidence of developmental etiology. Cornea. 1998;17:446–450. doi:10.1097/00003226-199807000-00018 [CrossRef]
- Akbaba M, Haciyakupoglu G, Uguz A, Karslioglu S, Karcioglu Z. Congenital intrascleral cyst. Clin Ophthalmol. 2011;5:583–585. doi:10.2147/OPTH.S19789 [CrossRef]
- AlQahtani E, Godoy F, Lyons C. Enlarging corneoscleral cyst in a 2-year-old girl. J AAPOS. 2015;19:389–391. doi:10.1016/j.jaapos.2015.03.020 [CrossRef]
- Kalamkar C, Mukherjee A. Primary corneoscleral cyst in a pediatric patient. Case Rep Ophthalmol. 2017;8:425–428. doi:10.1159/000477378 [CrossRef]
- Kim SW, Kim EK. Portable OCT-assisted surgical treatment of intracorneal pre-Descemet epithelial cyst: a case report. BMC Ophthalmol. 2017;17:160. doi:10.1186/s12886-017-0558-4 [CrossRef]
- Sano Y, Okamoto S, Nishida K, Sotozono C, Kinoshita S. Peripheral lamellar keratoplasty for corneoscleral cyst: three case reports. Cornea. 1999;18:233–236. doi:10.1097/00003226-199903000-00015 [CrossRef]