The Spine Journal 7 (2007) 720–727

Excision of an asymptomatic cervical intraduralneurenteric cyst through the anterior approach: a study

of two cases and a review of the literature

Mehdi Sasani, MDa,*, A. Fahir Ozer, MDa, B. Tunc Oktenoglu, MDa,Kamil Peker, MDb, M. Hakan Bozkus, MDa, Ali Cetin Sarioglu, MDa

aDepartment of Neurosurgery, American Hospital, Guzelbahce Sk. No: 20, 34365 Istanbul, TurkeybIstanbul Pathology Center, Valikonagi Cd. No: 125/2 Nisantasi, 34365 Istanbul, Turkey

Received 4 November 2006; accepted 18 December 2006

Abstract BACKGROUND: Spinal neurenteric cysts are very rare lesions, especially after the second decadeof life. They account for 0.3% to 0.5% of all spinal tumors and occur most commonly in ventrallocations. The cysts are usually removed via a posterior approach.PURPOSE: To present the clinical and radiologic results of patients with spinal neurenteric cystswho were treated via anterior approach procedures.STUDY DESIGN: This report is composed of two cervical neurenteric cyst cases that are com-pared with published studies.METHODS: We present two patients, 41- and 39-year-old women, each with a cervical intraduralneurenteric cyst. Both of these patients had apparent neck pain without neurological deficit. MRIrevealed neurenteric cysts located at C7 and C7–T1 levels. After anterior corpectomy, the intraduralcysts were removed, and then fusion was performed.RESULTS: The postoperative period went well. The follow-up cervical MRI studies were per-formed at 3, 6, and 18 months postoperatively, and there were no abnormalities found.CONCLUSIONS: This study has led to the conclusion that although neurenteric cysts are rare inadults, they can still be present with only persistent neck pain and without neurological deficits.This may lead to misdiagnosis. The importance of MRI is not controversial in the early diagnosis.An anterior approach may be considered the first preference for surgical technique in patients withventrally located neurenteric cysts. � 2007 Elsevier Inc. All rights reserved.

Keywords: Neurenteric cyst; Cervical intradural extramedullary mass; Anterior cervical corpectomy; Cervical intradural

cyst; Cervical anterior approach; Anterior cervical fusion

Introduction

Spinal neurenteric cysts are very rare lesions. Theyrepresent approximately 0.7% of tumors and 16% of cystsin the central nervous system and 0.3% to 0.5% of spinaltumors [1,2]. Most of these lesions have an extramedullaryintradural location and rarely arise intramedullarily [3–9].

FDA device/drug status: approved for this indication (cervical anterior

plate and screw, Totoplast Crista iliaca allograft bone).

Nothing of value received from a commercial entity related to this

manuscript.

* Corresponding author. Department of Neurosurgery, American Hos-

pital, Guzelbahce Sk. No: 20, 34365 Nisantasi, _Istanbul, Turkey.

E-mail address: sasanim@gmail.com (M. Sasani)

1529-9430/07/$ – see front matter � 2007 Elsevier Inc. All rights reserved.

doi:10.1016/j.spinee.2006.12.010

The pathogenesis of neurenteric cysts of the spinal cordis unclear, although the neurenteric cysts pathogenesis hasbeen suggested to be congenital in origin [10–12]. Neuren-teric cysts may occur as a result of the failure of notochordformation. [13,14]. These lesions are derived from dis-placed endodermal tissue. Neurenteric cysts are occasion-ally symptomatic, with neck pain and constriction of headmovement being prominent symptoms. They are usually di-agnosed in childhood and puberty [15]. Although the pos-terior approach is the usual surgical technique for thetreatment of this disease, the anterior approach and lateralapproach have been described by some authors [16–19].In this study, we present a report of two adult patients withasymptomatic neurenteric cysts that were removed via ananterior approach with a favorable outcome.

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Case reports

Case 1

A 41-year-old female patient was admitted with the com-plaint of slight neck pain for 9 months. Her past medical

history revealed that she had been treated for cervical degen-erative disc disease for 6 months and had been referred to thepsychiatric department with a diagnosis of psychosomaticdisorder. She had been given antidepressants for 3 months(amitriptiline 1�10 mg and a specific serotonin reuptakeinhibitor, paroxetine 1�40 mg).

Fig. 1. Cervical MRI scans of case 1: (a) preoperative sagittal T1 weighted, (b) sagittal T2 weighted, (c) axial T1 weighted, and (d) axial T2 weighted. MRI

shows obliteration of the spinal cord by the neurenteric cyst with regular enhancement.

722 M. Sasani et al. / The Spine Journal 7 (2007) 720–727

The neurological examination revealed no motor deficitor sensorial disorders, and there was only moderately con-striction of head movement in flexion and extension.Magnetic resonance imaging (MRI) of the cervical spinerevealed the presence of an anterior intradural extramedul-lary cystic lesion behind the C7 vertebral body. The cystwas hyperintense compared with cerebrospinal fluid onT1-weighted MRI and slightly hypointense on proton den-sity and T2-weighted sequences (Fig. 1). Cranial, thoracic,and lumbar MRI showed no pathological evidence.

Discectomies and C7 corpectomy were performed withvisualization via a surgical microscope. The dura was tight,expulsed, and without pulsation. A vertical small incisionwas made on the dura mater. The cystic lesion was ob-served to be attached to the ventral aspect of the spinalcord. Total resection was performed without tearing ofthe cyst membrane. The dura was stitched with a single su-ture (4-0 absorbable vicryl). The dural surface was rein-forced with artificial dura mater (duragen) and a piece offree fat tissue. Finally, artificial bone graft and anterior in-strumentation were performed. The cyst measured 25 mmin length and 10 mm in width (Fig. 2). The cystic contentwas mucoid in nature.

The histologic sections of the cyst wall showed a cysticlesion lined by a cuboidal to columnar epithelium contain-ing mucus resembling intestinal epithelium. No epithelialatypia was noted. The wall of the cyst was thin and edem-atous (Fig. 3).

The patient’s neck pain disappeared postoperatively. Shewas discharged in good condition on the third postoperativeday. The follow-up MRI studies were performed in postop-erative months 3, 6, and 18. No residual lesion or recur-rence of the lesion was observed (Fig. 4).

Fig. 2. The neurenteric cyst was totally removed and measures 25 mm in

length and 10 mm in width.

Case 2

A 39-year-old woman complained of neck pain for 1year. The medical treatment, including a painkiller (diclofe-nac Na), a muscle relaxant (dizanidine hydrochlorur), andphysical therapy, was not helpful. Neurological examina-tion determined no neurological deficit. The MRI studiesof the cervical spine showed anterior intradural extramedul-lary cyst (hypointense on T1 and hyperintense on T2) at theC7–T1 disc level (Fig. 5). First, anterior discectomy wasperformed at the C7–T1 level in addition to partial corpec-tomies of the lower part of the C7 and the upper part of theT1 vertebrae. As in the first case, a vertical small incisionwas made through the dura mater to expose the lesion.The cyst was mucoid lesions attached to the ventral aspectof the spinal cord. After total removal of the neurentericcyst, the dura was closed with 4-0 absorbable sutures andsupported with artificial dura mater and fat grafts. Fusionwas then performed with allograft crista iliaca bone, andanterocervical plates were applied.

The histologic sections of the cyst wall determined thatthe lesions were neurenteric cyst. The postoperative periodwas uneventful. The patient was discharged in goodcondition on the third postoperative day. The 3-, 6-, and18-month postoperative MRI showed resolution of theselesions and no recurrence (Fig. 6).

Discussion

Spinal cord neurenteric cysts are rare. They are mostcommonly found during the first decade of life[1,2,10,20–25]. The male:female ratio for development ofthese cysts is 2:1 [26]. The cervical canal and the cervico-thoracic junction are the most common locations. Anteriorcysts are always localized ventral or anterolateral to thespinal cord in both children and adults [9]. Agnoli et al.[2] reviewed 33 histologically verified neurenteric intraspi-nal cysts. The study’s findings showed that 18 cases werelocated in the cervicodorsal spine between C3 and T7

Fig. 3. Histopathological examination showed a cystic lesion resembling

intestinal epithelium.

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Fig. 4. Postoperative of case 1: (A) cervical MRI 3 months after the operation: (a) sagittal section and (b) axial section. The black arrow shows subarachnoid

space, and the white arrow shows plate and screw artifact. (B) Eighteen-month postoperative cervical MRI demonstrated no recurrence: (a) sagitttal plan T2

weighted and (b) axial T2 weighted section.

724 M. Sasani et al. / The Spine Journal 7 (2007) 720–727

Fig. 5. Case 2, preoperative (a) sagittal section T2 weighted and (b) axial section T2 weighted.

levels, 80% were intradural extramedullary lesions, and12% were intramedullary lesions. In the present cases, wefound the cysts to be in the same locations, but the only dif-ferences from the current published literature were the agesof our patients. Reviewing the literature revealed thatneurenteric cysts are most common in the first decade oflife, but the present cases were discovered after the thirddecade of life, which is very rare.

Symptoms and signs of neurenteric cysts are mainlycaused by compression on the spinal cord [10,13,27]. Forpatients who are asymptomatic for many years, the cystscompress the spinal cord slightly [9]. The symptoms arealso related to the size of the cysts, which cause meningealirritation; therefore, pain is the prominent symptom. Neuro-logical deficits can be noticed in untreated cases, and de-pending on the cyst level, motor and sensory disturbancescan occur. Symptoms of meningitis have ranged fromlow-grade meningeal irritation secondary to cyst fluid leak-age to acute pyogenic meningitis, which may result in ab-scess formation [25,28–31]. Newborns and infants canpresent with cyst fluid leakage symptoms and signs of men-ingitis [28]. There may be radiating pain, with the focalpoint of the pain in the affectual region of the spine[9,32]. Despite this, cervical neurenteric cysts may beasymptomatic for long periods of time, as in the presentedcases. These patients had only slight neck pain without neu-rological abnormalities. This type of presentation is likely

due to lack of continued compression on the spinal cord.Intermittent spinal cord compression has been ascribed tofluctuations in the size of the cyst and continued secretionof fluid by the columnar epithelium [9,25,33]. Therefore,in the beginning, it may be the lack of syptoms that causesmisdiagnosis and results in wrong treatment.

MRI provides the differential diagnosis of neurentericcysts better than other diagnosis methods such as computedtomography CT scans [10,11,14,34,35]. Bony anomalieswere clearly shown by CT scans. The frequent occurrenceof bony disorders mandates a thorough knowledge of theosseous structures to be encountered during the operation[9,36]. The high protein content of neurenteric cyst fluidusually appears on MRI as isointense or slightly hyperin-tense relative to cerebrospinal fluid on T1-weighted imagesand isointense or hyperintense on T2-weighted images[3,10,37]. When compared with CSF, no contrast enhance-ment is observed. This density characteristic of the cystfluid is likely an interplay between the protein content,which may be of CSF density or contain fat-like substancessimilar to that seen in epidermoids [9]. The lack of contrastenhancement of the cyst wall and the absence of a muralnodule on MRI are two significant findings that help todifferentiate these lesions from neoplastic lesions as intra-medullary tumors [38–40]. Nonneoplastic cystic lesions,such as arachnoid cysts, syringes, and teratomas, may showa very similar MRI appearance to neurenteric cysts

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Fig. 6. Postoperative of case 2: (a) 3 months after operation, lateral cervical X-ray film, sagittal T2-weighted and (b) axial T2-weighted section. (c) Eighteen

months postoperative, sagittal T2-weighted MRI scan showed no recurrence or instability.

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[38,41,42]. The diagnostic marker of an arachnoid cyst isthat the cerebrospinal fluid of patients with arachnoid cystsdoes not have a high protein content like that of patientswith neurenteric cysts. MRI usually shows increased signalon T2-weighted images with no cyst wall postcontrast en-hancement [43]. Intramedullarily located neurenteric cystsin the literature are reported to be very rare [7,8,9,44,45].

Neurenteric cysts are benign lesions; this criterion is thereason for the increased importance in achieving a success-ful outcome during the surgical procedure. The basic aim oftreatment is excision of the lesion to avoid neurologicaldeficits. A review of the literature shows that mostly sur-gery via the posterior approach has been performed, despitethe ventral location of the neurenteric cyst [46]. Althoughthe anterior cervical approach carries risks, such as theinjury of nearby structures, failure of fusion and graft dis-placement, and delayed formation of hematoma and cere-brospinal fluid leakage, the posterior approach has riskswith different, severe side effects from the anterior ap-proach. Complications associated with posterior proceduresare related to the degree of exposure, the neural element ex-posed, and the use of instrumentation and vascular elementinjuries [47,48]. The primary risks of cervical laminectomyinclude cord, dura, and root injuries. The vascular compli-cations, including vertebral artery injury and venous bleed-ing, may result in hematoma. Lateral mass screws requireprecise localization to avoid injury to the vertebral artery.Although the cyst is often ventral to the cord, a posteriorlateral approach usually provides the most direct avenueto resection. The cord is often displaced from the massand may be dissected free from the cord after sectioningof the dentate ligaments and aspiration of the cyst contents.Because of the viscous, mucinous contents, this proceduremay provide only partial collapse of the cystic mass. In ad-dition, total resection may be accomplished with tearing ofthe cyst membrane. Leakage of the cyst contents may resultin meningeal irritation in the posterior approach, whereasdirect exposure of the cyst in the anterior approach maycause total resection without rupturing of the cyst.

Obviously, the anterior approach to remove neurentericcysts that are ventrally localized and completely extrame-dullary in position is more satisfactory than the posteriorapproach [9]. In 1990, Koksal et al. [18] described an ante-rior approach to the craniocervical neurenteric cyst. Fouryears later, Devkota et al. [15] reported a case of an intra-dural neurenteric cyst of the cervical spine approachedthrough a central corpectomy. It is important to identifythe vascular anatomy of ventrally located lesions becausea posterior approach may compromise the abnormal vascu-lature [9,30,31]. In the posterior approach, the retraction ofthe spinal cord to reach the ventral location may causepermanent damages.

The other underlying point is surgery for the recurrenceof neurenteric cysts. Menezes and Traynelis [9] andMenezes and Ryken [29] described that there is no correla-tion between age, sex, and size and level of neurenteric cyst

recurrence. Partial resection is the major cause leading torecurrence of a neurenteric cyst. We believe that only a bi-opsy or aspiration of the cyst is not an adequate procedure;total resection of the cyst is the main goal, and it can beeasily performed via an anterior approach, without tearingof the cyst membrane to avoid meningeal irritation thatmay result in meningitis. The anterior approach does notcarry the risks of artery injury related to instrumentationlike posterior approach.

From this study, it can be concluded that although neu-renteric cysts are rare in adults, they can still be presentwith only persistent neck pain and without neurologicaldeficits. This may lead to misdiagnosis. The importanceof MRI is not controversial in the early diagnosis. Theanterior approach may be considered the first preferencefor surgical technique in patients with ventrally locatedneurenteric cysts.

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