Choristomatous orbital cysts are most commonly dermoid and epidermoid cysts, less commonly conjunctival dermoids with adnexal structures, and rarely respiratory epithelial cysts. Choristomatous cystic orbital lesions rarely cause strabismus without a common clinical presentation of proptosis and eyelid swelling. We describe a child with worsening strabismus and amblyopia but no proptosis or clinically obvious lesion, in whom imaging revealed a large choristomatous respiratory epithelial cyst of the orbit.
A 3-year-old girl with a history of partial accommodative esotropia and amblyopia of the right eye presented for patching follow-up. She had been observed in clinic since the age of 16 months, at which time a conjunctival mass in the right temporal quadrant had been noted and diagnosed as a lipodermoid. The patient had no history of trauma or sinus disease.
At this visit, her visual acuity was 20/70 in the right eye and 20/40 in the left eye. Cycloplegic refraction by retinoscopy showed stable +6.75 sphere in both eyes, in agreement with her current spectacles. Motility examination showed a −1.5 limitation to abduction of the right eye, which was a new finding. In the right eye, there was a 16 prism diopter residual esotropia in primary gaze at distance and 12 prism diopter esotropia in primary gaze at near with correction. This was increased from her examination 2 months prior, when only a 6 prism diopter esotropia was noted at distance and 4 prism diopter esotropia at near with correction.
Slit-lamp examination of the right eye was notable for a newly observed soft fullness of the lateral upper eyelid that was mildly tender to palpation. The development of nasal globe dystopia without proptosis was noted. A temporal subconjunctival lesion of the right eye was seen in primary and left gaze (Figures 1A–1B). Fundus examination did not show evidence of choroidal folds.
External photograph showing temporal subconjunctival lesion of the right eye in (A) primary gaze and (B) left gaze. Magnetic resonance imaging of the orbits showed 2.5 × 2.0 × 2.8 cm lobular non-enhancing lesion in the extraconal space of the right orbit. T1-weighted contrast enhanced images are shown in (C) axial and (D) coronal orientations, notable for globe compression and medial displacement of the lateral rectus. (E) Computed tomography of the orbits shows cystic lesion with bony involvement of the frontal process of the zygomatic bone. Photomicrographs of the orbital cyst (hematoxylin–eosin stain) show (F) non-ciliated columnar epithelium (original magnification × 50) and (G) ciliated columnar epithelium (original magnification ×200). (H) External photograph showing appearance at 6 weeks postoperatively.
Magnetic resonance imaging of the orbits was performed, demonstrating the clinically correlated globe dystopia and displacement of the lateral rectus muscle (Figures 1C–1D). The lesion involved the lateral osseous wall of the right orbit, and a computed tomography scan was obtained to evaluate bony involvement prior to resection (Figure 1E).
Lateral orbitotomy with bone removal and replacement was performed. During dissection of the cyst from the orbital bones, the cyst wall was compromised with leakage of keratinaceous debris, followed by careful dissection of the entire cyst wall. Gross pathologic examination of the excised tissue revealed a 28 × 18 × 7 mm red/tan cystic tissue specimen, containing a soft beige material. Microscopic examination showed a cyst lined by both keratinizing squamous epithelium and non-ciliated and ciliated columnar epithelium (Figures 1F–1G).
Follow-up examination at 6 weeks postoperatively showed equalization of vision between both eyes, with 20/25 visual acuity in each eye at distance, full extraocular motility, 5 prism diopters of esotropia at distance, and only a flicker of esotropia at near (Figure 1H).
In choristomas, abnormal sequestration of tissue during intrauterine development results in microscopically normal cells and tissues in anatomically unexpected locations. Choristomatous orbital cysts are most commonly dermoid and epidermoid cysts, less commonly conjunctival dermoids with adnexal structures, and rarely respiratory epithelial cysts. Respiratory epithelial cysts are simple primary orbital cysts lined by respiratory epithelium.1,2 Orbital cysts with respiratory epithelial lining are uncommon developmental cysts and generally occur secondary to chronic obstruction of the paranasal sinuses, resulting in sino-orbital mucoceles.3 Acquired respiratory epithelial cysts are typically nasally located. If a respiratory epithelial cyst occurs without associated sinus disease or orbital trauma and is not found to have any communication with a paranasal sinus, intrauterine sequestration of respiratory epithelium is postulated.4 This is additionally suggested by temporal location, not adjacent to the paranasal sinuses, as shown in three cases reported by Mee et al.5
Case reports in the literature cite multiple instances of respiratory epithelial cysts in the orbit,4–6 with common presenting symptoms of proptosis, mild abduction deficits, and eyelid swelling. Only one of these cases reports a child with a respiratory epithelial cyst,5 and in this case vision was not affected and the globe was not displaced. In our case, the lack of sinus disease on imaging, no history of trauma, and temporal location all indicated a choristomatous origin. This is the first report in the literature of a child developing strabismus and amblyopia secondary to a choristomatous respiratory epithelial cyst of the orbit.
Mass lesions causing esotropia are usually detectable secondary to incomitance of the strabismus, proptosis, globe dystopia, or an externally visible tumor. Additional signs can include vision changes, pupil irregularities, diplopia, choroidal folds, optic disc edema or atrophy, orbital congestion, eyelid retraction, or blepharoptosis. Our patient presented with strabismus and a lesion thought to be a lipodermoid was noted. The orbital cyst was only suggested by a mild fullness of the lateral conjunctiva. This case illustrates the importance of maintaining a reasonable suspicion of orbital lesions in patients presenting with childhood strabismus and amblyopia.
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