Orbital conjunctival epithelial inclusion cysts are a rare complication of strabismus surgery. A subconjunctival cystic mass with translucent fluid is the most common presentation. The authors describe a case of an epithelial inclusion cyst presenting as an occult orbital mass during reoperation strabismus surgery almost 70 years after strabismus surgery. [J Pediatr Ophthalmol Strabismus 2013;50:e15–e17.]
From the Departments of Pediatric and Ocular Genetics (DRL, BNW) and the Ocular Pathology (RCE), Wills Eye Institute, Philadelphia, Pennsylvania.
The authors have no financial or proprietary interest in the materials presented herein.
Correspondence: Barry N. Wasserman, MD, Department of Pediatric Ophthalmology and Ocular Genetics, Wills Eye Institute, 840 Walnut Street, Suite 1210, Philadelphia, PA 19107. E-mail: firstname.lastname@example.org
Received: June 07, 2012
Accepted: February 28, 2013
Posted Online: April 02, 2013
Orbital conjunctival epithelial inclusion cysts are a rare complication of strabismus surgery. A subconjunctival cystic mass with translucent fluid is the most common presentation. We describe a case of an epithelial inclusion cyst presenting as occult orbital mass during reoperation strabismus surgery almost 70 years after strabismus surgery.
A 71-year-old man presented complaining of the left eye drifting outward for the past 30 years. He had a history of amblyopia in the left eye. He had one strabismus surgery 68 years prior to presentation, and the extraocular muscles operated on at that time were unknown. His ocular history was significant for bilateral upper eyelid ptosis and dermatochalasis for which he underwent bilateral levator resection and blepharoplasty 2 years prior to presentation.
On examination, visual acuity was 20/40 in the right eye and 20/200 in the left eye without an afferent pupillary defect. Strabismus, evaluated by modified Krimsky technique, revealed a left comitant exotropia of 50 prism diopters. Extraocular motility was otherwise full. Slit-lamp examination showed prior blepharoplasty scars and nuclear sclerosis in the right eye and conjunctival scarring in the nasal bulbar conjunctiva and a posterior chamber intra-ocular lens in the left eye. He did not have proptosis, external masses, or globe dystopia.
The diagnosis was consecutive exotropia, and the patient elected to have a left medial rectus resection and left lateral rectus recession. During surgery, the surgeon encountered scar tissue surrounding the medial rectus muscle. The muscle insertion was 10 mm posterior to the limbus, indicating previous surgery on this muscle. An approximately 1 cm soft, cystic mass was detected firmly attached to the nasal border of the medial rectus muscle posterior to its insertion (Figure 1). The mass was not connected to sclera or periosteum. The mass was entirely resected. The surgery was then completed using non-adjustable sutures without further complications. At the 6-month postoperative visit, the patient appeared orthophoric by modified Krimsky test without visual complaints.
Figure 1. Intraoperative photographs of an orbital mass discovered during strabismus surgery. The left globe is abducted, and the muscle hook is posterior to the insertion of the medial rectus muscle. (Left) A round orbital mass is seen obscuring the view of the medial rectus muscle. The mass was dissected of its attachments and appeared cystic and adjacent to the nasal border of the medial rectus muscle. (Right) A muscle hook is posterior to the insertion of the medial rectus muscle.
Macroscopically, the cyst measured 1 cm in diameter and was filled with gelatinous material lost during processing. Histopathologically, the cyst had an empty branching lumen and was lined by a layer of nonkeratinized epithelium resembling limbal conjunctiva. The epithelium varied in caliber and had no goblet cells or epidermal appendages. No lacrimal gland tissue was identified. The histopathologic findings were consistent with a postoperative conjunctival epithelial inclusion cyst (Figure 2).
Figure 2. Histopathology discloses a cyst with empty branching lumen. The nonkeratinized epithelial lining of the cyst (seen at higher magnification below) varies in caliber and resembles limbal conjunctiva. Goblet cells are not present. The findings are consistent with a postoperative conjunctival inclusion cyst (top = hematoxylin–eosin, original magnification ×10; bottom = hematoxylin–eosin, original magnification ×50).
Epithelial inclusion cysts are a rare complication of strabismus surgery and typically associated with horizontal recti likely because of prior surgery on those muscles.1 Patients usually present with either a bluish-gray translucent subconjunctival mass or incomitant strabismus. The cysts are believed to arise from epithelial cells of the conjunctiva disrupted during strabismus surgery, possibly from suture material with conjunctival cells coursing the scleral tunnel.2
Most epithelial inclusion cysts occurring after strabismus surgery are visible on examination, although they may only be seen when the patient moves the eye away from the primary position. Our patient’s cyst was occult, not visible on slit-lamp examination, and not causing restrictive strabismus. This may have been because the cyst was located posteriorly in the orbit. We found only one report of a cyst not clinically detectable that presented as incomitant strabismus resembling a slipped muscle.3
Previous reports show time to discovery of the cyst ranges from 2 to 52 years following strabismus surgery.4–6 The cyst in our case was discovered 68 years following strabismus surgery, which is the longest ever reported and the first case to present at the time of surgery without evidence on preoperative examination. We suggest considering epithelial inclusion cyst in the differential diagnosis of an occult orbital mass discovered any time after strabismus surgery.
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