Optic Nerve Cysts


Article Author:
Sravanthi Vegunta


Article Editor:
Bhupendra Patel


Editors In Chief:
John Schweitzer


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Frank Smeeks
Kristina Soman-Faulkner
Radia Jamil
Patrick Le
Sobhan Daneshfar
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Pritesh Sheth
Hassam Zulfiqar
Navid Mahabadi
Steve Bhimji
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Mark Pellegrini
James Hughes
Beata Beatty
Nazia Sadiq
Hajira Basit
Phillip Hynes
Tehmina Warsi


Updated:
1/13/2019 11:32:27 PM

Introduction

The topic of optic nerve cysts encompasses a variety of etiologies including idiopathic, neoplastic, saccular or tubular expansions of the meninges, traumatic, or iatrogenic. Additionally, this topic also includes congenital cystic eye or microphthalmos with cyst, which often involves the optic nerve.

Etiology

The cysts may be caused by a variety of etiologies including idiopathic, associated with meningiomas, meningoceles, arachnoid cysts, neuroepithelial cysts, and post-traumatic or postoperative cysts. Specifically, optic nerve sheath meningocele is a dilation of the optic nerve sheath, and expansion of the subarachnoid or subdural cerebrospinal fluid (CSF)-filled space around the optic nerve. An arachnoid cyst is a benign proliferation of normal fibrovascular tissue of the leptomeninges around the optic nerve. Neuroepithelial cysts are rare lesions that typically present in the ventricles or cerebral parenchyma. They have rarely been reported in the intracranial portion of the optic nerve.[1]

Cysts may also be iatrogenic. For example, Naqvi et al.[2] reported 2 cases of cysts that formed after optic nerve sheath fenestration.

Epidemiology

The frequency of cysts is difficult to determine given the varied etiologies of the cysts across age groups. The cysts may also be asymptomatic and never diagnosed. For example, per Lunardi et al.,[3]  only 31 cases of optic sheath meningocele are reported in the literature.

Pathophysiology

The pathophysiology of primary arachnoid cysts is unclear. In the setting of traumatic arachnoid cysts or post-optic nerve sheath fenestration iatrogenic cysts, Akor et al.[4] proposed that trauma results in optic nerve sheath entrapment of secretory neuroepithelial cells and cyst formation. In the setting of congenital cysts, there may be entrapment of these cells during embryogenesis. Lunardi et al.[3] suggest that congenital arachnoid cysts develop through a diverticulum or blind pocket within the arachnoid membrane.

Optic nerve sheath meningoceles may be caused by the abnormal bony structure of the orbital apex. The subarachnoid space is narrowest near the optic canal. Congenital narrowing here could cause meningoceles.[3]

In some cases of optic nerve cysts, dilation of the optic nerve sheath complex could be secondary to proximal neoplasm, vascular hamartoma, or cranio-orbital fracture. In these cases, the neoplastic tissue or fracture acts like a ball valve allowing CSF to enter one direction into the sheath.[3]

Neuroepithelial cysts may be caused by developmental abnormalities when there is incomplete closure along the optic fissure. A more severe version of this condition is colobomatous cyst also known as microphthalmia with cyst.[1] The superior end of the embryonic fissure does not close at the time of 10 to 13 mm embryo. The edges of the fissure evert as they oppose one another, forming a cystic structure. These cysts walls have collagenous fibers and poorly differentiated neuroepithelium and neuroglial tissue. Cysts are connected to the sclera. They may be filled with eosinophilic material or photoreceptor segments.[5]

Vision loss is thought to be due to compression of the optic nerve itself.

Histopathology

Histopathology of optic nerve sheath meningoceles and arachnoid cysts shows normal meninges.[6]

A colobomatous optic nerve cyst is composed of 2 layers. The inner layer has retinal architecture and is derived from primitive neuroretinal tissue. The outer layer has vascularized connective tissue continuous with the sclera.[6]

Mehta et al.[1] reported on a case of a neonate with a neuroepithelial cyst that was resected. Histopathology showed the cyst was lined by simple cuboidal epithelium without cilia or goblet cells. No neural tissue was present; however, immunohistochemical staining was positive for S100, a marker of neural tissue.[1]

History and Physical

Patients with optic nerve cysts may be asymptomatic or present with nonspecific orbital or neurological findings. In the setting of arachnoid cysts, visual acuity can range from 20/20 to NLP.

Garrity et al.[7] reported in a case series of thirteen patients with optic nerve sheath meningocele who presented with a headache, decreased vision, proptosis, afferent pupillary defect, enlarged blind spot, optic disc edema, shunt vessels at optic disc, and tortuous retinal veins.

Colobomatous cyst often involves the optic nerve itself. As the lesion grows, typically inferiorly, it may produce a palpable mass behind the lower eyelid. In some cases, lowering the lower eyelid can reveal a dark uveal pigmentation to the mass. Bilateral cases may be associated with systemic diseases such as chiasmal glioma, polycystic kidney, trisomy, or Edward syndrome.[1]

Evaluation

Lesions that can be localized on history and physical exam to the optic nerve or brain should be imaged with brain and or orbital MRI with and without contrast. Imaging can elucidate the size of the cyst, consistency, and effect on surrounding structures with imaging. Typically arachnoid cysts and meningoceles will have signal intensity equal to that of CSF, dark on T1 and bright on T2, without enhancement after intravenous (IV) contrast administration.[6]

Optic nerve sheath meningoceles appear as tubular-cystic enlargement of the optic nerve and optic nerve sheath complex on CT and MRI. On coronal MRI both the optic nerve and sheath appear dilated in a "bull's eye" pattern. Off-axis sagittal views are the best for showing widening of the meninges with a fluid-filled space.[6]

In children with microphthalmos, orbital ultrasound should be used to determine the organization of ocular structures. US can also be used to visualize cysts in these patients. MRI is more helpful than CT in characterizing the content of the cyst, which is usually similar to vitreous or CSF. MRI also be used to visualize the relationships or connections, communications between the cyst, nerve, and globe. Visual potential can be evaluated with retinal electrophysiology.[5]

Treatment / Management

Given the variety of etiologies of optic nerve cysts, treatment is not uniform or established in the literature.

Our understanding of treatment is mostly based on case studies or case series. The main concern with surgical resection or drainage of these cysts is that it can be associated with significant morbidity due to the risk of optic nerve transection. Additionally, surgeons have to ensure that the cyst itself is not a coloboma in an eye with stable vision as drainage can result in drainage of intraocular contents.

Saari et al.[8] reported an interesting case of arachnoid cyst of intraorbital optic nerve in 1977 before imaging was available. The patient presented with slight pain on eye movements, and transient attacks of blurred vision, optociliary shunt vessels, significant optic disc edema with hemorrhages and macular edema, and shallowing of the anterior chamber all in the left eye only. The patient had a lumbar puncture with an opening pressure of 150 mm H20. The lesion was thought to be a meningioma. Optic nerve sheath fenestration showed forceful and voluminous egress of CSF. Histopathology of the resected optic nerve sheath was normal. Nine months after the procedure, the left eye was blind with significant optic nerve atrophy. The authors recommend prompt diagnosis and drainage of arachnoid cysts to preserve vision.

Naqvi et al.[2] reported 2 cases of post optic nerve sheath fenestration optic nerve cysts. The patients had loculated CSF surrounded by fibrous proliferation at the site of previous optic nerve sheath fenestration. One patient presented with pain, proptosis, and visual loss 9 months after the initial procedure. The other patient presented with vision decline and choroidal folds. Both patients underwent repeat fenestration during which the closed sheath with fibrosis and outpouching was visualized. Larger windows were created in the sheaths.

For optic nerve sheath meningoceles, Lunardi et al.[3] reviewed 31 cases and recommended early surgical management of optic nerve sheath decompression in patients who present with a rapid decrease in visual acuity over 3 to 6 months. They endorsed the improvement of visual function with minimal morbidity.

Mehta et al.[1] reported a case of neuroepithelial cyst that presented in a 6 week old with proptosis, exotropia, RAPD, and normal anterior and posterior segment ophthalmic exam. The cyst was drained and resected by anterior orbitotomy through an upper eyelid crease incision. The patient's presenting signs including RAPD resolved postoperatively. The authors iterate that the goal of treatment in patients who present with optic nerve cysts is to prevent or reverse vision loss.

Colobomatous cysts can be aspirated if they are cosmetically unacceptable. In many cases, if the cyst returns after repeat aspirations, the eye and cyst may be removed, and the socket may be fitted with prosthetics.[6]

Differential Diagnosis

The differential diagnosis should include optic nerve neoplasms such as meningiomas and optic nerve gliomas, vascular malformations, and systemic conditions such as neurofibromatosis and Von Hippel Lindau. Increased CSF pressure due to a cerebral lesion, vascular lesion, or idiopathic intracranial hypertension should be considered especially if optic nerve sheath dilatation is bilateral.

Prognosis

The outcomes of surgical management versus observation are varied in case reports and case series. Lunardi et al.[3] report that 13 out of 33 patients underwent surgical drainage of optic nerve sheath meningoceles. Five out of 13 had vision improvement.

Enhancing Healthcare Team Outcomes

Orbital pain, vision loss, and proptosis are symptoms that patients may present to the primary care physician or general ophthalmologist prior to referral to oculoplastics surgeon, neuro-ophthalmologist, or neurosurgeon. Pediatricians, internal medicine, and family physicians should be aware of the risk of vision loss if a referral is delayed. Imaging of the orbits and brain is appropriate prior to referral. Additionally, the oculoplastic surgeon, neuro-ophthalmologist, and neurosurgeon may need to work together to monitor the patient after surgery for a recurrence of the lesion.


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Optic Nerve Cysts - Questions

Take a quiz of the questions on this article.

Take Quiz
After optic nerve sheath fenestration, a patient develops a cyst around the optic nerve at the site of fenestration. What is the proposed mechanism of this cyst formation?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 1-year-old girl presents to the clinic. Her father states that there is a fullness to the left lower lid and seems like there is a "marble" growing in it or behind it. On examination, the right lower lid has a black uveal mass. The eye appears small with a misshapen, irregular cornea. The anterior segment structures seem disorganized. The plan is to do some imaging to evaluation this mass further. What imaging modality would be appropriate for this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A one-year-old girl with right inferior colobomatous cyst returns for follow up. Her parents bring her back to your clinic at age 2. They have been following with a pediatric ophthalmologist who determined after extensive ERG, VEP, clinical, and imaging tests that she had no light perception and nonfunctional intraocular contents. The size of the inferior cyst is growing and is cosmetically unappealing. They would like to discuss treatment. What is the next best option for this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 30-year-old woman presents for routine examination and has left optic nerve shunt vessels. She had MRI imaging one year ago for migraine type headaches that are now controlled with medications. The left optic nerve looks cyst-like and slightly dilated compared to the right nerve just posterior to the globe. Optic nerve sheath meningocele is suspected. What is the proposed pathophysiology of this lesion?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 38-year-old female is sent by the neuro-ophthalmologist for an optic nerve sheath fenestration as there appears to be a large cyst arising from the optic nerve medially which they feel is causing compression of the optic nerve with visual field loss. Which of these surgical approaches is the least advisable when performing the optic nerve sheath fenestration?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Optic Nerve Cysts - References

References

Mehta VJ,Chelnis JG,Nickols HH,Mawn LA, Neuroepithelial Cyst of the Optic Nerve in a Newborn. Ophthalmic plastic and reconstructive surgery. 2017 May/Jun     [PubMed]
Naqvi SM,Thiagarajah C,Golnik K,Lee A,Kersten R,Nerad J, Optic nerve cyst-like formation presenting as a delayed complication of optic nerve sheath fenestration. Ophthalmic plastic and reconstructive surgery. 2014 May-Jun     [PubMed]
Lunardi P,Farah JO,Ruggeri A,Nardacci B,Ferrante L,Puzzilli F, Surgically verified case of optic sheath nerve meningocele: case report with review of the literature. Neurosurgical review. 1997     [PubMed]
Akor C,Wojno TH,Newman NJ,Grossniklaus HE, Arachnoid cyst of the optic nerve: report of two cases and review of the literature. Ophthalmic plastic and reconstructive surgery. 2003 Nov     [PubMed]
Slamovits TL,Kimball GP,Friberg TR,Curtin HD, Bilateral optic disc colobomas with orbital cysts and hypoplastic optic nerves and chiasm. Journal of clinical neuro-ophthalmology. 1989 Sep     [PubMed]
Shields JA,Shields CL, Orbital cysts of childhood--classification, clinical features, and management. Survey of ophthalmology. 2004 May-Jun     [PubMed]
Garrity JA,Trautmann JC,Bartley GB,Forbes G,Bullock JD,Jones TW Jr,Waller RR, Optic nerve sheath meningoceles. Clinical and radiographic features in 13 cases with a review of the literature. Ophthalmology. 1990 Nov     [PubMed]
Saari M,Mustonen E,Palva A,Jokinen K,Reunanen M, Arachnoid cyst of the intraorbital portion of the optic nerve with unilateral disc oedema and transient shallowing of the anterior chamber. A case report. Acta ophthalmologica. 1977 Dec     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of Pathology-Neuropathology. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for Pathology-Neuropathology, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in Pathology-Neuropathology, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of Pathology-Neuropathology. When it is time for the Pathology-Neuropathology board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study Pathology-Neuropathology.