Neurology India
menu-bar5 Open access journal indexed with Index Medicus
  Users online: 2791  
 Home | Login 
About Editorial board Articlesmenu-bullet NSI Publicationsmenu-bullet Search Instructions Online Submission Subscribe Videos Etcetera Contact
  Navigate Here 
 Resource Links
  »  Similar in PUBMED
 »  Search Pubmed for
 »  Search in Google Scholar for
  »  Article in PDF (738 KB)
  »  Citation Manager
  »  Access Statistics
  »  Reader Comments
  »  Email Alert *
  »  Add to My List *
* Registration required (free)  

  In this Article
 »  References
 »  Article Figures
 »  Article Tables

 Article Access Statistics
    PDF Downloaded84    
    Comments [Add]    
    Cited by others 8    

Recommend this journal


Table of Contents    
Year : 2012  |  Volume : 60  |  Issue : 1  |  Page : 123-124

Intramedullary arachnoid cyst: Report of two cases

Department of Neurosurgery, SMS Medical College, Jaipur (Rajasthan), India

Date of Submission29-Oct-2011
Date of Decision20-Nov-2011
Date of Acceptance25-Dec-2011
Date of Web Publication7-Mar-2012

Correspondence Address:
Rashim Kataria
Department of Neurosurgery, SMS Medical College, Jaipur (Rajasthan)
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.93618

Rights and Permissions

How to cite this article:
Kataria R, Sinha V D, Chopra S. Intramedullary arachnoid cyst: Report of two cases. Neurol India 2012;60:123-4

How to cite this URL:
Kataria R, Sinha V D, Chopra S. Intramedullary arachnoid cyst: Report of two cases. Neurol India [serial online] 2012 [cited 2023 Nov 30];60:123-4. Available from:


Arachnoid cysts are benign lesions and usually asymptomatic. The origin of arachnoid cysts is not clear. The hypothesis proposed by Hyndman and Gerber [1] suggests that the cysts arise from the misplaced cellular remnants. The degenerating cells of the arachnoid trabeculae leads to an increase in the osmotic effect within the cyst, causing its enlargement. [2] A valve-like mechanism for enlargement of the cyst is also postulated. Intramedullary arachnoid cysts are rare and only nine cases have been reported so far. All previously reported patients, except one, belonged to the pediatric age group and none involved the conus medullaris. [3],[4],[5],[6],[7],[8],[9],[10] Here, we report two cases with intramedullary arachnoid cyst in the conus, confirmed on histopathology examination.

A nine-year-old female child presented with a one-year history of low backache, dribbling of urine, and numbness in both lower limbs of six months duration. Examination showed weakness in both ankles, saddle anesthesia, and decreased anal tone. Magnetic Resonance Imaging (MRI) of the thoracolumbar spine showed an intramedullary, non-enhancing Cerebrospinal Fluid (CSF) intensity cystic lesion at the conus medullaris ([Figure 1]- preoperative). She underwent L1-L2 laminectomy, dorsomedian myelotomy, and cyst decompression. The cyst contained clear fluid. Partial removal of the cyst wall was done as it was adherent to the cord tissue. She showed gradual improvement in power at both ankle joints and improved bladder sensations at six weeks follow-up. A repeat MRI ([Figure 1]- postoperative) of the thoracolumbar spine at six-month follow-up did not show any evidence of cyst.
Figure 1: (a,b) Preoperative sagittal T1 and T2W MRI of the TL spine in Case 1, showing a cystic intramedullary lesion at the conus medullaris. The lesion is isointense to the CSF. (c) Postoperative MRI of the same patient at six-month follow-up confirms removal of the cyst

Click here to view

Another case, a 40-year-old female presented with progressive paraparesis and urinary symptoms of six months duration. MRI of thoracolumbar spine [Figure 2] showed a well-defined intramedullary non-enhancing mass with CSF intensity at L1. A dorsomedian myelotomy was done and the cyst decompressed. The cyst contained a clear CSF-like fluid. As the wall was adherent to the cord, only partial excision of the wall could be done. She regained power in the bilateral ankle joints and was continent at the four-week follow-up.
Figure 2: Sagittal and axial preoperative T1W MRI of the thoracolumbar spine in Case 2 showing cystic intramedullary lesion at the conus medullaris

Click here to view

Histopathological examination of the cyst wall in both patients revealed fibrous connective tissue lined by arachnoid cells, suggestive of an arachnoid cyst [Figure 3].
Figure 3: Photomicrograph of a section of the cyst wall illustrating its histological features with fibrous wall lined by arachnoid cells. Hematoxylin and Eosin (H and E, ×40)

Click here to view

The first case of intramedullary arachnoid cyst was reported by Aithala et al. [3] in 1999. Of the nine cases of intramedullary arachnoid cysts reported so far, eight were in the pediatric age group; thus, probable embryonic malformations can be speculated as an etiological factor [Table 1]. [3],[4],[5],[6],[7],[8],[9],[10] In a recent study of 10 symptomatic cervical spinal intradural arachnoid cysts carried out by Lee and Cho, [11] eight cysts were found to be in the pediatric age group, and none was intramedullary in location. The characteristic MRI findings of an intramedullary arachnoid cyst include a cystic lesion of CSF intensity, hypointense to the normal cord tissue in T1-weighted images and hyperintense on T2-weighted images with no contrast uptake and no perilesional edema. Important differential diagnosis of a cystic conus lesion includes a terminal (fifth) ventricle, [12] focal syringomyelia, epidermoid, and ependymoma. However, it is often not possible to differentiate radiologically between an arachnoid cyst, focal syrinx, and terminal ventricle. The major pathological difference among the terminal ventricle, arachnoid cyst, and focal syrinx is that the epithelial lining of an arachnoid cyst is made of arachnoid (meningothelial) cells. The terminal ventricle and focal syrinx are lined by ependymal cells and neuronal cells, respectively.
Table 1: Literature review of patients with spinal intramedullary arachnoid cyst

Click here to view

Management of benign cystic conus lesions (arachnoid cyst, focal syrinx, and terminal ventricle) remains the same irrespective of the pathology. Hence, it is not always mandatory as well as not possible to establish the diagnosis preoperatively. The treatment of the symptomatic intramedullary arachnoid cyst includes dorsomedian or dorsal root entry zone myelotomy with wide decompression of the cyst and removal of the cyst wall as much as possible in order to improve the clinical symptoms. Complete excision of the cyst is often not possible because the wall is adherent to the cord. In both of our patients, the cyst was decompressed via a dorsal myelotomy and most of the cyst wall was removed, leaving behind a small portion of the wall adherent to the cord. The other treatment option is wide fenestration of the cyst with or without shunting to the subarachnoid space.

 » References Top

1.Hyndman OR, Gerber WF: Spinal extradural cysts, congenital and acquired. Report of cases. J Neurosurg 1946;3:474-86.  Back to cited text no. 1
2.Sharma A, Sayal P, Badhe P, Pandey A, Diyora B, Ingale H. Spinal intramedullary arachnoid cyst. Indian J Pediatr 2004;71:1444-6.  Back to cited text no. 2
3.Aithala GR, Sztriha L, Amirlak I, Devadas K, Ohlsson I. Spinal arachnoid cyst with weakness in the limbs and abdominal pain. Pediatr Neurol 1999;20:155-6.  Back to cited text no. 3
4.Goyal A, Singh AK, Singh D, Gupta V, Tatke M, Sinha S, et al. Intramedullary arachnoid cyst. J Neurosurg 2002;96:104-6.  Back to cited text no. 4
5.Sharma A, Sayal P, Badhe P, Pandey A, Diyora B, Ingale H. Spinal intramedullary arachnoid cyst. Indian J Pediatr 2004;71:65-7.  Back to cited text no. 5
6.Sharma A, Karande S, Sayal P, Ranadive N, Dwivedi N. Spinal intramedullary arachnoid cyst in a 4-year-old girl: a rare cause of treatable acute quadriparesis: case report. J Neurosurg 2005;102:403-6.  Back to cited text no. 6
7.Ghannane H, Haddi M, Aniba K, Lmejjati M, Ait Ben Ali S. Symptomatic intramedullary arachnoid cyst. Report of two cases and literature review. Neurochirurgie 2007;53:54-7.  Back to cited text no. 7
8.Guzel A, Tatli M, Yilmaz F, Bavbek M. Unusual presentation of cervical spinal intramedullary arachnoid cyst in childhood: case report and review of the literature. Pediatr Neurosurg 2007;43:50-3.  Back to cited text no. 8
9.Lmejjati M, Aniba K, Haddi M, Hakkou M, Ghannane H, Ait Ben Ali S. Spinal intramedullary arachnoid cyst in children. Pediatr Neurosurg 2008;44:243-6.  Back to cited text no. 9
10.Medved F, Seiz M, Baur MO, Probst EN, Tuettenberg J. Thoracic intramedullary arachnoid cyst in an infant Case report. J Neurosurg Pediatrics 2009;3:132-6.  Back to cited text no. 10
11.Lee HJ, Cho DY. Symptomatic spinal intradural arachnoid cysts in the pediatric age group: description of three new cases and review of literature. Pediatr Neurosurg 2001;35:181-7.  Back to cited text no. 11
12.Liccardo G, Ruggeri F, De Cerchio L, Floris R, Lunardi P. Fifth ventricle: An unusual cystic lesion of the conus medullaris. Spinal Cord 2005;43:381-4.  Back to cited text no. 12


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]

This article has been cited by
1 Long-Term Recurrent Intramedullary Arachnoid Cyst: Case Report and Literature Review
Hatem B. Afana, Salman F.M. Kananeh, Rajamagesh Duraisamy, Abdulkadir Farah, Nicandro Figueiredo
Asian Journal of Neurosurgery. 2023;
[Pubmed] | [DOI]
2 Ventriculus terminalis or conus medullaris arachnoid cyst: a diagnostic dilemma
Sergio G Núñez Báez, Orlando De Jesus, Eduardo J Labat, Caleb E Feliciano
BMJ Case Reports. 2022; 15(5): e250812
[Pubmed] | [DOI]
3 Intramedullary arachnoid cyst: A rare cause of medullary compression
Oscar Niyonzima, Magatte Gaye Sakho, Alidji Ibrahima Fondo, Mohameth Faye, Jean Michel Nzisabira, Mbagnick Bakhoum
International Journal of Case Reports and Images. 2022; 13(2): 35
[Pubmed] | [DOI]
4 Conus medullaris intramedullary arachnoid cyst- case report and review of the literature
Vishal Vishnu Thakur, Ranjit Devidas Rangnekar, Shashank Aroor, Krishnakumar Kesavapisharady, Mathew Abraham
Surgical Neurology International. 2021; 12: 370
[Pubmed] | [DOI]
5 Congenital Spinal Cysts: An Update and Review of the Literature
Sarah E. McNutt, Oliver D. Mrowczynski, Jessica Lane, Ryan Jafrani, Pratik Rohatgi, Charles Specht, R. Shane Tubbs, T. Thomas Zacharia, Elias B. Rizk
World Neurosurgery. 2021; 145: 480
[Pubmed] | [DOI]
6 Recurrent Spinal Intramedullary Arachnoid Cyst: Case Report and Literature Review
Toshiya Ichinose, Katsuyoshi Miyashita, Shingo Tanaka, Nozomu Oikawa, Masahiro Oishi, Iku Nambu, Masashi Kinoshita, Mitsutoshi Nakada
World Neurosurgery. 2020; 138: 68
[Pubmed] | [DOI]
7 Adult-onset spastic paraparesis: An approach to diagnostic work-up
Lana Zhovtis Ryerson,Joseph Herbert,Jonathan Howard,Ilya Kister
Journal of the Neurological Sciences. 2014;
[Pubmed] | [DOI]
8 Spinal intramedullary arachnoid cyst: case report and literature review
Federica Novegno,Giuseppe Umana,Licia Di Muro,Bernardo Fraioli,Francesco Fraioli Mario
The Spine Journal. 2013;
[Pubmed] | [DOI]


Print this article  Email this article
Online since 20th March '04
Published by Wolters Kluwer - Medknow