External photographs, computed tomographic images, and magnetic resonance images. External photographs show the patient before (A) and 2 weeks after (B) dacryocystorhinostomy. Computed tomography was performed for sagittal (C) and coronal (D) views of the anterior orbit. Midorbit coronal (E) and retrobulbar coronal (F) views on computed tomography show inferonasal bony asymmetry. Postdacryocystorhinostomy magnetic resonance imaging with sagittal T1-weighted (G) and coronal T1-weighted fat saturation (H) views shows biphasic mass contents. Arrows indicate the mass; arrowheads, the bony anomaly.
Lesion histopathological analysis. Conjunctiva-like stratified squamous epithelium (A), lacrimal sac–like cuboidal epithelium5 (B), chronic dacryocystitis5 (C), and stratified squamous epithelium next to nonciliated cuboidal epithelium (D) (hematoxylin-eosin, original magnification ×20). E, Stratified squamous epithelium with periodic acid–Schiff–positive goblet cells (arrows), hair follicles (asterisk), and sebaceous glands (arrowhead) resembling caruncle (periodic acid–Schiff, original magnification ×20).
Tan JCH, Lucarelli MJ, Albert DM, Gentry LR. Complex Choristoma Masquerading as a Dacryocystocele. Arch Ophthalmol. 2009;127(6):819-828. doi:10.1001/archophthalmol.2009.108
Orbital dermoid cysts are choristomas believed to arise during development from sequestered ectodermal rests. The cysts are lined by keratinized stratified squamous epithelium, contain adnexal structures, and are often attached to superotemporal orbital bone.1,2 A variant of the orbital dermoid cyst, the conjunctival dermoid cyst, is lined by nonkeratinized epithelium with goblet cells and tends to be found anteronasally in orbital soft tissue without bony attachment.3,4
A 35-year-old man had a 15-year history of chronic epiphora and an erythematous, soft, nontender swelling near his right medial canthus (Figure 1A). He was considered to have a dacryocystocele. Despite an external dacryocystorhinostomy, his swelling persisted (Figure 1B).
Subsequent computed tomography showed a well-circumscribed mass inferomedially in the right orbit (Figure 1C and D) that was extrinsic to the nasolacrimal system but encroached on the nasolacrimal sac fossa and its proximal duct. It measured 22 mm anteroposteriorly. There was bony asymmetry between the orbits, with the right inferomedial wall adjacent to the lesion more angular in profile. This bony asymmetry was evident even posterior to the mass, along its presumed attachment more posteriorly in the orbit (Figure 1E and F). Computed tomographic images and magnetic resonance images (Figure 1G and H) showed that the cyst's contents were biphasic with signal characteristics indicating fat superiorly and proteinaceous material inferiorly.
The mass was removed by anterior transcutaneous orbitotomy. It adhered to soft tissue posteriorly in the orbit, and significant blunt dissection was needed to detach it. The removed lesion was thin walled and soft, containing pale cheesy material with fine hairs.
Histopathological analysis showed that part of the cyst wall resembled conjunctiva (Figure 2A), whereas another part resembled upper lacrimal sac epithelium5 (Figure 2B and D). The lacrimal sac removed at dacryocystorhinostomy had chronic inflammatory cells and scarring (Figure 2C). A further part of the cyst wall resembled caruncle (Figure 2E).
Conjunctival dermoid cysts are choristomas thought to arise from cells destined to become the conjunctiva.3,4,6 Our patient's lesion had features typifying previously reported conjunctival dermoid cysts, but it also had other atypical features suggestive of caruncular and lacrimal sac epithelium, a relatively posterior orbital attachment, and associated bony anomaly. That the lesion's contents were mixed and in different phases is commensurate with its different (secretory) epithelia. Mass effect of the choristoma presumably compromised nasolacrimal drainage in our patient and caused a dacryocystocele and low-grade dacryocystitis.
Our case had many features in common with that of a recent report by Dutton et al.6 Both patients were young adults who had large cysts with relatively posterior orbital attachment and similarly biphasic contents radiologically. Dutton and colleagues excised their patient's recurrent lesion twice; the first resembled a classic dermoid cyst histologically, but the second resembled a conjunctival dermoid cyst. These histological entities may well have coexisted in the same lesion but were simply sampled separately at each surgery (Alan D. Proia, MD, PhD, written communication, June 28, 2007). That a choristoma in the posterior orbit can contain different ectodermally derived entities is certainly possible, as our case and that of Dutton and colleagues show.
Lacrimal drainage compression by a choristoma caused this unusual clinical manifestation. The case highlights the additional notion that choristomas containing conjunctiva may show varied histological features whose identification requires appropriate sampling and analysis. Elements resembling conjunctiva, lacrimal sac, and caruncle coexisting in a choristoma might attract speculation that the precursor ectodermal cells of these entities lie close enough to each other during development or that they have a common progenitor. If these cells thus ectopically sequester before differentiation or divergence, then the structures would come to lie together as a complex choristoma. Alternatively, cells sequestering after differentiation would yield a simple choristoma such as the conjunctival dermoid cyst.
Correspondence: Dr Tan, Department of Ophthalmology and Visual Sciences, University of Wisconsin, 2870 University Ave, Madison, WI 53705 (firstname.lastname@example.org).
Financial Disclosure: None reported.
Funding/Support: This work was supported in part by an unrestricted grant from Research to Prevent Blindness, New York, New York, to the Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison.
Previous Presentation: This paper was presented in part at the Spring Meeting of the American Society of Ophthalmic Plastic and Reconstructive Surgery; June 23, 2007; Key Largo, Florida.