Conjunctival Inclusion Cyst

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 by Michael T Yen, MD on May 4, 2021.


Conjuctival Inclusion Cysts are benign cystic lesions lined with a thin non-keratinizing epithelia, containing serous fluid.

Disease Entity

Conjunctival Cyst
ICD-9 DATA 372.75
ICD-10 DATA H11.44

Conjunctival Cyst is recognized by the following codes as per the International Classification of Diseases (ICD) nomenclature:

ICD-9

ICD-10

  • ICD-10 DATA
    • H11.44 Conjunctival Cysts
    • H11.441 Conjunctival cysts, right eye
    • H11.442 Conjunctival cysts, left eye
    • H11.443 Conjunctival cysts, bilateral
    • H11.449 Conjunctival cysts, unspecified eye


Other links

Figure 1.Patient 1- This photograph shows a perilimbic conjunctival inclusion cyst, formed two years after a pterygium surgery with conjunctival grafting, at the same site.

Disease

Inclusion cysts are benign cysts filled with clear serous fluid containing shed cells or mucous material ( Figure 1).[1]Inclusion cysts constitute 80% of all cystic lesions of the conjunctiva. The average onset age is 47 and occurrency is equally in both sexes.[2]

They are formed from an inclusion of the conjunctival epithelium into the proper substance, forming a central cystic cavity due to epithelial cell proliferation. Cyst wall is composed of non-keratinised lining epithelium and connective tissue. [3]It can either be primary or secondary, and are usually asymptomatic. Treatment is required if discomfort develops or any impairment of function due to the size, but treatment is usually expectant.[1]

Etiology

Primary conjunctival inclusion cysts are congenital, and secondary cysts can be spontaneous or, most commonly, due to inflammatory conditions of the conjunctiva[4], such as pterygium, pingueculitis[5], chronic keratoconjunctivitis[6] and pyogenic granuloma[7], or following ocular trauma[8] or surgery, such as cataract [9], strabismus[10], enucleation[11] or scleral buckle placement[12].

Risk Factors

The following have been cited for secondary conjunctival inclusion cyst:

  • Inflammatory conditions of the conjunctiva (e.g. pterygium, pingueculitis[5], chronic keratoconjunctivitis[6] or pyogenic granuloma[7])
  • Trauma[8]
  • Surgery[9][10][11][12]
  • Subtenonanesthesia[13]

General Pathology

According to Stedman's Medical Dictionary definition, cyst means an abnormal vesicle containing gas, fluid or semi-solid material, with a membranous framework. It can be developed in various locations e.g., eyelids, conjunctiva and anterior segment.[14] Post-traumatic or surgery cystic formation are often seen.[15]

Conjunctival inclusion cysts are derived from an inclusion of the conjunctival epithelium into the proper substance, forming a central cystic cavity due to epithelial cell proliferation. Cyst wall is composed of layers of non-keratinised lining epithelium and connective tissue.[3]

Pathophysiology

Excessive invagination of the caruncular epithelium or fornix during embryonic development leads to the formation of the primary inclusion cyst.[16] The presentation of these cysts varies from birth to old age.[4] On the other hand, secondary inclusion cysts can occur either naturally or under inflammatory condition of the conjunctiva. Anything that develops detachment of a portion of conjunctival epithelium, can cause a secondary inclusion cyst, such as surgery or trauma.[8] Subtenonanesthesia has also been described as a possible cause.[13]

In addition, it is known that cystic formation depends on inflammatory processes, therefore the immune system is responsible for the outbreak of these processes. Individual factors, such as autoimmune diseases, can also contribute to change immune response resulting in tissue-damaging immune processes.[15]

Primary prevention

Primary conjunctival inclusion cysts can not be prevented, as it is a congenital disease. Avoiding conjunctival inflammatory processes and ocular trauma can reduce the chance of developing a secondary inclusion cyst.

Diagnosis

History

Patient may be asymptomatic, being diagnosed with inclusion conjunctival cyst as an examination finding, or symptomatic. In symptomatic cases, patient may complain of a "round mass" inside the eye, which may be associated with an increased cyst size or foreign body sensation. It is also common a previous history of ocular trauma or surgery.

Physical examination

Figure 2. Patient 2 - Ectoscopy exam showing a conjunctival inclusion cyst in the lower bulb-tarsal conjunctiva region. This patient developed this cyst spontaneously, with no apparent risk factors (absence of an active inflammatory process or history of previous surgery/trauma).

Diagnosis of conjunctival inclusion cyst is essentially clincal. Typical clinical features consists of painless cystic masses of small to moderate size.[4] The histopathological examination ratifies the diagnostic hypothesis. It is important to perform a complete eye examination: ectoscopy (Figure 2), visual acuity, extrinsic eye motility, pupillary reflexes, slit lamp examination (measuring the size of the cyst, assessing characteristics of its wall and interior content) (Figure3). It is also important to evaluate signs of previous trauma or previous eye surgery, or active inflammatory processes.

Signs

Figure 3. Patient 2- This is a slit lamp photograph, which illustrates a large conjunctival inclusion cyst. It is possible to observe the translucency of the conjunctival inclusion cyst wall.
Figure 4. Patient 1- This slit lamp photograph illustrates a pseudohypopyon in a conjunctival inclusion cyst, developed 2 years after pterygium excision with autologous conjunctiva transplantation. There is fluid of epithelial cells depositing in the bottom of the cyst and forming a pseudohypopyon.

During examination, conjunctival inclusion cysts presents as a cystic lesion that originates from the conjunctiva. It usually presents with a thin-translucent wall (Figure 3). If the fluid has epithelial cells, they can go to the bottom of the cyst and form a pseudohypopyon (Figure 4).

Symptoms

Small conjunctival inclusion cysts are generally asymptomatic or only cause mild sensations indicating the presence of a foreign body. Although, larger cysts can cause pain, motility disturbance, visual defect or refractive error, and cosmetics concerns.

In a clinical-histopathological study that analyzed different varieties of conjunctival cysts[4], the most common symptoms were, in decreasing order:

  1. Progressive increase in size of cyst
  2. Cosmetic disfigurement
  3. Foreign body sensation
  4. Proptosis
  5. Ocular motility restriction
  6. Blurred vision

Clinical diagnosis

Diagnosis is based on previous history and physical examination.

Diagnostic procedures

The diagnosis of conjunctival inclusion cyst is clinical and confirmed by anatomopathology; however, there are some imaging diagnostics that can be useful. The use of imaging modalities is helpful for both preoperative planning and surgical decision-making and, also, to confirm cystic characteristics.

  • Ultrasound biomicroscopy (UBM)
  • Anterior Segment Optical Coherence Tomography (AS-OCT)
  • Computed Tomography Scan (CT-SCAN)

Laboratory test

Conjunctival Inclusion Cysts are diagnosed clinically, therefore, laboratory tests are not required.

Histopathology

The American Academy of Ophthalmology's Pathology Atlas contains a virtual microscopy image of Conjuctival Inclusion Cyst .

Differential diagnosis

Check Eyewiki´s Conjunctival Epithelium Neoplasms page for more differential diagnosis.

Management

The conduct can either be expectant or interventionist, depending on the size of the cyst and the patient's complaint.

General treatment

Excision of conjunctival inclusion cyst is the definitive treatment. In cases patient presents to emergency room with a complaint of eye discomfort, it is possible to aspirate the cyst in the slit lamp, under topical anesthesia of proparacaine 0.5 % on the ocular surface and, with the aid of a needle caliber 27, aspirate the cyst. Care must be taken not to puncture the eyeball during the procedure. Patient should be referred for surgical treatment and follow up even after the procedure.

Medical therapy

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Medical follow up

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Surgery

The conjunctival inclusion cyst excision can be done under local topical anesthesia with 0.5% proparacaine, associated with subconjunctival infiltration of lidocaine around the cyst. Non-traumatic tweezer can be used to assist divulsion step. A small incision is made and the blunt tip of scissors introduced between the cyst and tenon capsule, to separate the cyst from the surrounding tissue. After total divulsion in all circumference, next step is to divulse carefully the cyst base, as its ruptures is common during the dissection. Depending on the size of the cyst, the excess tissue is removed. Removing the cyst intact decreases chances of recurrence. There are some options in relation to the exposed scleral bed: it is possible to use the bare sclera technique, which involves allowing the bare scleral bed to re-epithelialize, using autologous conjunctival transplant or amniotic membrane. Lastly, refer the material to anatomopathological examination.

Check the video below for a better understanding:

Surgical follow up

The follow-up time for each patient who underwent surgical excision of the cysts varies. It is recommended a minimum period of 1 year after surgery for the recurrence and development of any complications.

Complications

As the cysts are thin walled, rupture is common during excision. Recurrence is the main postoperative concern. Careful and intact removal of cyst is necessary to prevent recurrence.[4]

Prognosis

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Additional Resources

  • Images ilustrating conjunctival inclusion cyst (A) and histopathological (B).
    © 2021 American Academy of Ophthalmology

A: Epithelial inclusion cysts may follow conjunctival trauma.

B: The cyst is lined by nonkeratinizing, stratified squamous epithelium, consistent with conjunctiva.

You can also visit AAO website to check out this multimedia.



References

  1. 1.0 1.1 Nath K, Gogi R, Zaidi N, Johri A. Cystic lesions of conjunctiva (a clinicopathogical study). Indian J Ophthalmol. 1983: 31(1):1-4.
  2. 2. Lu J, Chu F, Chen K. Conjunctival Inclusion Cyst. Hong Kong Journal of Emergency Medicine. 2013;20(3):184-185.
  3. 3.0 3.1 Johnson DW, Bartley GB, Garrity JA, Robertson DM. Massive epithelium-lined inclusion cysts after scleral buckle. Am J Ophthalmol. 1992;113(4): 439-42.
  4. 4.0 4.1 4.2 4.3 4.4 Thatte S, Jain J, Kinger M, Palod S, Wadhva J, Vishnoi A. Clinical study of histologically proven conjunctival cysts. Saudi J Ophthalmol. 2015;29(2):109-115.
  5. 5.0 5.1 Dias VG, Martins MP, Bezzon AKT, Aguni JS, Cavalheiro R. Cisto de inclusão conjuntival gigante associado a pterígio: relato de caso. Arq. Bras. Oftalmol. 2004;67(5):831-833.
  6. 6.0 6.1 Lee Seung-Won, Lee Seung-Chan, Jin Kyung-Hyun. Conjunctival inclusion cysts in long standing chronic vernal keratoconjunctivitis. Korean J Ophthalmol. 2007;21(4)
  7. 7.0 7.1 Suzuki K, Okisaka S, Nakagami T. The contribution of inflammatory cell infiltration to conjunctival inclusion cyst formation. Nippon Ganka Gakkai Zasshi. 2000;104(3):170-3.
  8. 8.0 8.1 8.2 Barishak Robert Y., Barrak E., Lazar M. Episcleral traumatic conjunctival inclusion cyst. BJO. 1977;61:29–301
  9. 9.0 9.1 Shylajanarayanappa, Dayananda S, Dakshayini M, Babu S, Prabhakaran G. Conjunctiva inclusion cyst following small incision cataract surgery. Indian J Ophthalmol. 2010;58(5):423–425.
  10. 10.0 10.1 Metz HS, Searl S, Rosenberg P, Sterns G. Giant orbital Cyst after strabismus surgery. J AAPOS. 1999;3(3):185-7.
  11. 11.0 11.1 Jünemann A, Holbach LM. Epitheliale Riesenimplantationszyste 50 jahre nach Enukleation ohne Orbitaimplantat. Kin Monatsbl Augenheilkd. 1998;212 (2):127-8.
  12. 12.0 12.1 Johnson DW, Bartley GB, Garrity JA, Robertson DM. Massive epithelium-lined inclusion cysts after scleral buckle. Am J Ophthalmol. 1992;113(4): 439-42.
  13. 13.0 13.1 Vishwanath M.R., Jain A. Inclusion cyst after subtenon. Br J Anaesthesia. 2005;95:825–826.
  14. Stedman TL. Cyst. In: Stedman TL. Stedman's medical dictionary. 26th ed. Baltimore: Williams & Wilkins; 1995. p.429.  
  15. 15.0 15.1 Dias VG, Martins MP, Bezzon AKT, Aguni JS, Cavalheiro R. Cisto de inclusão conjuntival gigante associado a pterígio: relato de caso. Arquivos Brasileiros de Oftalmologia 2004; 67(5): 831-833.
  16. Imaizumi M, Nagata M, Matsumoto CS, Nakalruka K, Kachima K. Primary conjunctival epithelial cyst of orbit. Int Ophthalmol. 2007;27:269–271.