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Ventrally placed craniovertebral junction arachnoid cysts in children: a report of 2 cases and literature review
Surgical Neurology 68 (2007) 85 – 88 www.surgicalneurology-online.com
Imaging
Ventrally placed craniovertebral junction arachnoid cysts in children: a report of 2 cases and literature review Sandeep Mohindra, MCh, FRCSEd4, Sunil Kumar Gupta, MCh, Rajesh Chhabra, MCh, Rahul Gupta, MCh, Anand Kumar, MCh, Bishan Dass Radotra, MD Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India Received 26 June 2006; accepted 18 July 2006
Abstract
Background: Arachnoid cysts at the craniovertebral junction are uncommon, and all the reported cases had location posterior to the brain stem. We describe 2 cases of ventral arachnoid cysts among children. Case Description: Two children, in their first decades of life, presented with spastic quadriparesis without complaints of raised intracranial pressure. Magnetic resonance imaging showed large, ventrally located cystic lesions compressing the brain stem and extending from posterior fossa to the lower level of C4 vertebra. Both patients underwent surgery via midline posterior fossa approach and fenestration of cysts along with partial excision. Both patients made complete recovery and are asymptomatic in the long-term outcome. Conclusion: Ventral arachnoid cysts at the craniovertebral junction present in the pediatric age group because of compression of corticospinal tracts. These patients have good long-term outcome after fenestration and partial cyst excision. D 2007 Elsevier Inc. All rights reserved.
Keywords:
Arachnoid cyst; Craniovertebral junction
1. Introduction
2. Case 1
Primary arachnoid cysts of the craniovertebral junction are uncommon lesions, constituting only 1% of total intracranial mass lesions, and 10% of all such cysts are located above the vermis in the posterior fossa [15,18]. These cysts are congenital in origin [10,16], containing CSF-like fluid with in intraarachnoidal space. All of the reported cases have been in adults, and all had cysts located in the posterior fossa or craniovertebral junction, usually dorsal to the neural tissues. We report 2 unique cases of craniovertebral junction arachnoid cysts presenting in the pediatric age group and situated ventral to the brain stem.
An 8-year-old boy presented with complaints of stiffness and weakness in all 4 limbs for the last 4 months. There was history of dull ache at the back of the neck but no complaints of headache or vomiting. There was no history of trauma. On examination, the child had spastic quadriparesis (grade 4/5) and could barely walk with scissoring gait. He also had urgency of micturition for the past 1 month. Magnetic resonance imaging revealed a large cystic lesion ventral to brain stem, starting from clivus reaching inferiorly up to the C4 vertebra. There was no hydrocephalus. The contents of the cystic lesion had the same intensity as that of CSF on MRI scans (Fig. 1A-C). The patient underwent suboccipital craniotomy and C1 laminotomy. The dura was opened in an inverted Y-shaped fashion. A large cyst was noted ventral to the brain stem, more on the left side, providing a corridor to fenestrate the cyst wall. Cisterna magna was opened, and the cyst wall was excised partially, with minimal traction on the lower cranial nerves. Primary dural closure was done, and bony anatomy
Abbreviations: C, cervical; CSF, cerebrospinal fluid; CT, computed tomography; ICP, intracranial pressure; MRI, magnetic resonance imaging. 4 Corresponding author. Tel.: +91 0172 2693124, 2756699, +91 9815535675; fax: +91 0172 2744401. E-mail address: [email protected] (S. Mohindra). 0090-3019/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2006.07.024
86
S. Mohindra et al. / Surgical Neurology 68 (2007) 85 – 88
Fig. 1. A: Sagittal section of the MRI scan (T1-weighted) showing a large hypointense lesion compressing the medulla from the front. The lower limit of the lesion is reaching the fourth cervical vertebra (case 1). B: Sagittal section of the MRI scan (T2-weighted) showing a hyperintense lesion located ventral to brain stem and having the same intensity as that of CSF, indicating it to be an arachnoid cyst (case 1). C: Axial section of the MRI scan at the level of the brain stem showing a large cystic lesion located right anterolateral to the brain stem (case 1).
Fig. 2. A: Sagittal section of the T1-weighted MRI scan showing a hypointense mass lesion located anterior to the brain stem (case 2). B: Sagittal section of the T2-weighted MRI scan showing a large hyperintense cystic lesion anterior to the brain stem. C: Axial section of the T2-weighted MRI scan showing hyperintense cystic lesion anterior and right to the brain stem. The ribbon-shaped compressed brain stem is noteworthy.
S. Mohindra et al. / Surgical Neurology 68 (2007) 85 – 88
was restored. Postoperatively, the patient made an eventless recovery and remains asymptomatic at 2 years follow-up. 3. Case 2 A 9-year-old girl presented with complaints of slowly progressive weakness of all 4 limbs and gait difficulty. She was having difficulty holding fine objects, and there was a change in handwriting. On examination, the child could walk with support (motor power grade 4/5), and all 4 limbs were severely spastic. There were no bladder complaints. Suspecting it to be a case of craniovertebral junction anomaly, plain radiographs were done, which did not reveal any abnormality. Magnetic resonance imaging scan of craniovertebral junction revealed a large cystic lesion ventral to the brain stem, which extends both above and below the foramen magnum, causing posterior displacement and kinking of the brain stem (Fig. 2A-C). There was no hydrocephalus. Fenestration with partial excision of cyst wall was carried out via midline posterior fossa approach. Postoperatively, the child improved rapidly, and normal gait was restored. The patient has remained asymptomatic at 10 years follow-up. 4. Discussion Eight cases of craniovertebral junction arachnoid cysts have been reported up to now [2,3,5,11,15,18,19]. All the reported cases (except one case with a laterally placed cyst) have described dorsally located posterior fossa, infravermian arachnoid cysts, extending into upper cervical canal and pushing the cord anteriorly. All reported cases were adults, except 1 patient aged 16 years (Table 1). The cases reported here are unique because the cysts were located ventrally and the clinical presentation was in the pediatric age group. The presentation of cysts has been attributed to the direct compression of neural structures or
87
interference with CSF circulation. The late presentation in adult age of these congenital cysts is possibly due to relatively slow growth or expansion [15]. Thus, the mean age of diagnosis of reported cysts in the literature was 38 years. The 2 cases reported here presented at the age of 8 and 9 years. We believe that this early presentation was possibly related to the anterior location. Being ventral, there was relatively early interruption of pyramidal pathways leading to clinical presentation in the form of spasticity in childhood, and the imaging diagnosis also tends to be early as these cannot be confused with a large cisterna magna. The differential diagnoses of a cystic lesion at this region are neuroenteric cysts [1,6,12] and developmental dermoid or epidermoid cysts [4,17], which can also present with similar clinical complaints. Diffusion-weighted MRI reveals no water restriction in the case of arachnoid cysts, whereas epidermoid cysts show water restriction [3]. These developmental epidermoid or dermoid cysts also present in the first 2 decades of life, and the associated spina bifida or dermal sinus tract may be an indicator of their presence. Arachnoid cysts have signal intensity identical to that of CSF (Figs. 1A-C and 2A-C). The high intensity on T1weighted and hyperintense signal on T2-weighted MRI images similar to that of CSF helped to diagnose arachnoid cysts in both of our cases. Epidermoid cyst is another important differential diagnosis, as cases of developmental dermoid/epidermoid cysts have been reported at the craniovertebral junction [4]. Commonly developing in the cerebellopontine cistern and parasellar region, these cysts usually have low signal and high signal on T1-weighted and T2-weighted magnetic resonance images, respectively [17]. Diffusion-weighted images show iso-hyperintensity compared with the brain and can be distinguished from other cysts [17]. Neuroenteric cysts at the craniovertebral junction have also been reported [1,6,12]. These are endothelium-lined
Table 1 Summary of craniovertebral junction arachnoid cysts reported in literature Author
Age/Sex
Symptoms
Radiology
Cyst location
Treatment
Follow-up
Outcome
Kuroiwa et al (1991) [11]
59/Male
MRI
Dorsal to brainstem
Partial excision
–
–
Bhatia et al (1992) [2]
22/Male
CT myelogram
Dorsal to brainstem
Partial excision
1 mo
Good
Takanashi et al (1995) [19]
36/Male
CT and MRI
Dorsal to brainstem
Partial excision
–
–
Fukushima et al (1996) [5]
54/Female
MRI
Dorsal to brainstem
Partial excision
1 mo
Good
Shukla et al (1998) [18]
16/Male
Posttraumatic, spastic gait Urinary hesitancy, spastic paraparesis Cerebellar symptoms, right arm dysesthesia Raised ICP, head and neck pain High cord compression
MRI
Dorsal to brainstem
3 wk
Good
Pego-Reigosa et al (2000) [14] Price et al (2001) [15] Cakirer et al (2004) [3]
48/Male
MRI
Dorsal to brain stem
Cystoperitoneal shunt Partial excision
–
–
MRI MRI
Dorsal to brainstem Left of brainstem
Complete excision Partial excision
18 mo –
Good –
Present case
8/Male
MRI
Ventral to brainstem
Partial excision
2y
Good
Present case
9/Female
MRI
Ventral to brainstem
Partial excision
10 y
Good
37/Female 27/Female
Gait problems, spastic paraparesis Raised ICP Head and neck pain, left arm weakness, dysesthesia High cord compression, urinary hesitancy High cord compression
88
S. Mohindra et al. / Surgical Neurology 68 (2007) 85 – 88
resonance imaging scans with T1-, T2-, and diffusionweighted sequences help in diagnosis and in the differentiation from other lesions located at this location. Fenestration with partial cyst wall excision gives good results. References
Fig. 3. Microphotograph showing a collapsed cystic structure lined by arachnoid cells. Multilayering of cells can be seen at places.
cysts located ventrally, and the correct preoperative diagnosis may not always be possible [1]. Diffusion-weighted MRI images of neuroenteric cysts reveal low-signal intensity similar to that seen in the arachnoid cyst. Neuroenteric cysts may be associated with vertebral anomalies such as segmentation fusion defects [9]. Hence, evaluation of bony anatomy and histopathological examination of the lesion are necessary to establish a correct diagnosis (Fig. 3). Primary arachnoid cysts are embryonic malformations due to an error in the differentiation of early endomeningeal tissue [2,13]. Secondary arachnoid cysts may form as a consequence of meningitis, trauma, and hemorrhage [2,13,15]. The progressive expansion of such arachnoid cysts is attributed to ball-valve mechanism between the cyst and the subarachnoid space [7], or active fluid secretion by the cells lining the cyst wall [8]. Fenestration with partial excision of cyst wall remains the surgical treatment of choice [2,15]. Suboccipital craniotomy and laminotomy using drill system can provide good anatomic reconstruction and minimal problems in long-term follow-up, especially among pediatric patients. Both of our patients remain asymptomatic at long-term follow-up. A cystoperitoneal shunt may be needed for a recurrent cyst [15]. 5. Conclusion Arachnoid cysts situated ventral to the brain stem and presenting in the pediatric age group have not been reported previously. These lesions present with spasticity because of compression over the corticospinal tracts. Magnetic
[1] Abe K, Oyama K, Mori K, Ishimaru S, Eguchi M, Maeda M. Neurenteric cyst of the craniocervical junction—case report. Neurol Med Chir (Tokyo) 1999;39:875 - 80. [2] Bhatia S, Thakur RC, Radotra BD, Kak VK. Craniospinal intradural arachnoid cyst. Postgrad Med J 1992;68:829 - 30. [3] Cakirer S. Arachnoid cyst of the craniospinal junction: a case report and review of the literature. Acta Radiol 2004;45:460 - 3. [4] Chandra PS, Gupta A, Mishra NK, Mehta VS. Association of craniovertebral and upper cervical anomalies with dermoid and epidermoid cysts: report of four cases. Neurosurgery 2005;56:1155. [5] Fukushima Y, Sato M, Taguchi J, Sasaki M, Kanai N, Hayakawa T. Craniospinal arachnoid cyst: case report [Article in Japanese]. No Shinkei Geka 1996;24:75 - 9. [6] Fuse T, Yamada K, Kamiya K, Inagaki H. Neurenteric cyst at the craniovertebral junction: report of two cases. Surg Neurol 1998;50: 431 - 6. [7] Galassi E, Tognetti F, Gaist G, Frank F. Arachnoid cysts of the middle cranial fossa; a clinical and radiological study of 25 cases treated surgically. Surg Neurol 1980;14:211 - 9. [8] Go RG, Houthoff HJ, Blaauw EH, Havinga P, Hartsuiker J. Arachnoid cysts of sylvian fissure. Evidence of fluid secretion. J Neurosurg 1984; 60:803 - 13. [9] Kapoor V, Johnson DR, Fukui MB, Rothfus WE, Jho HD. Neuroradiologic-pathologic correlation in a neurenteric cyst of the clivus. AJNR AJNR Am J Neuroradiol 2002476 - 9. [10] Kollias S, Ball WS, Prenger EC. Cystic malformations of the posterior fossa: differential diagnosis clarified through embryologic analysis. Radiographics 19931211 - 31. [11] Kuroiwa T, Takeuchi E, Yamada K, Ohta T, Miyaji Y, Onomura T. An intradural arachnoid cyst of the craniovertebral junction; a case report [Article in Japanese]. No Shinkei Geka 1991;19:1097 - 9. [12] Lazareff JA, Hoil Parra JA. Intradural neurenteric cyst at the craniovertebral junction. Childs Nerv Syst 1995;11:536 - 8. [13] Naidich TP, McLone DG, Radkowski MA. Intracranial arachnoid cysts. Pediatr Neurosci 1985-86;12:112 - 22. [14] Pego-Reigosa R, Branas-Fernandez F, Martinez-Vazquez F, CortesLaino JA. Craniospinal intradural arachnoid cyst. Arch Neurol 2000; 57:128. [15] Price SJ, David KM, O’Donovan DG, Aspoas AR. Arachnoid cyst of the craniocervical junction: case report. Neurosurgery 2001;49:212 - 5. [16] Robinson RG. Congenital cysts of the brain: arachnoid malformations. Prog Neurol Surg 1971;4:133 - 74. [17] Shakudo M, Inoue Y, Ohata K, Tanaka S. Neurenteric cyst with alteration of signal intensity on follow-up MR images. AJNR Am J Neuroradiol 2001;22:496 - 8. [18] Shukla R, Sharma A, Vatsal DK. Posterior fossa arachnoid cyst presenting as high cervical cord compression. Br J Neurosurg 1998; 12:271 - 3. [19] Takanashi Y, Mochimatsu Y, Shyudo T, Yamamoto I. A case report of an arachnoid cyst in the craniovertebral junction [Article in Japanese]. No To Shinkei 1991;47:68 - 70.
Imaging
Ventrally placed craniovertebral junction arachnoid cysts in children: a report of 2 cases and literature review Sandeep Mohindra, MCh, FRCSEd4, Sunil Kumar Gupta, MCh, Rajesh Chhabra, MCh, Rahul Gupta, MCh, Anand Kumar, MCh, Bishan Dass Radotra, MD Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India Received 26 June 2006; accepted 18 July 2006
Abstract
Background: Arachnoid cysts at the craniovertebral junction are uncommon, and all the reported cases had location posterior to the brain stem. We describe 2 cases of ventral arachnoid cysts among children. Case Description: Two children, in their first decades of life, presented with spastic quadriparesis without complaints of raised intracranial pressure. Magnetic resonance imaging showed large, ventrally located cystic lesions compressing the brain stem and extending from posterior fossa to the lower level of C4 vertebra. Both patients underwent surgery via midline posterior fossa approach and fenestration of cysts along with partial excision. Both patients made complete recovery and are asymptomatic in the long-term outcome. Conclusion: Ventral arachnoid cysts at the craniovertebral junction present in the pediatric age group because of compression of corticospinal tracts. These patients have good long-term outcome after fenestration and partial cyst excision. D 2007 Elsevier Inc. All rights reserved.
Keywords:
Arachnoid cyst; Craniovertebral junction
1. Introduction
2. Case 1
Primary arachnoid cysts of the craniovertebral junction are uncommon lesions, constituting only 1% of total intracranial mass lesions, and 10% of all such cysts are located above the vermis in the posterior fossa [15,18]. These cysts are congenital in origin [10,16], containing CSF-like fluid with in intraarachnoidal space. All of the reported cases have been in adults, and all had cysts located in the posterior fossa or craniovertebral junction, usually dorsal to the neural tissues. We report 2 unique cases of craniovertebral junction arachnoid cysts presenting in the pediatric age group and situated ventral to the brain stem.
An 8-year-old boy presented with complaints of stiffness and weakness in all 4 limbs for the last 4 months. There was history of dull ache at the back of the neck but no complaints of headache or vomiting. There was no history of trauma. On examination, the child had spastic quadriparesis (grade 4/5) and could barely walk with scissoring gait. He also had urgency of micturition for the past 1 month. Magnetic resonance imaging revealed a large cystic lesion ventral to brain stem, starting from clivus reaching inferiorly up to the C4 vertebra. There was no hydrocephalus. The contents of the cystic lesion had the same intensity as that of CSF on MRI scans (Fig. 1A-C). The patient underwent suboccipital craniotomy and C1 laminotomy. The dura was opened in an inverted Y-shaped fashion. A large cyst was noted ventral to the brain stem, more on the left side, providing a corridor to fenestrate the cyst wall. Cisterna magna was opened, and the cyst wall was excised partially, with minimal traction on the lower cranial nerves. Primary dural closure was done, and bony anatomy
Abbreviations: C, cervical; CSF, cerebrospinal fluid; CT, computed tomography; ICP, intracranial pressure; MRI, magnetic resonance imaging. 4 Corresponding author. Tel.: +91 0172 2693124, 2756699, +91 9815535675; fax: +91 0172 2744401. E-mail address: [email protected] (S. Mohindra). 0090-3019/$ – see front matter D 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.surneu.2006.07.024
86
S. Mohindra et al. / Surgical Neurology 68 (2007) 85 – 88
Fig. 1. A: Sagittal section of the MRI scan (T1-weighted) showing a large hypointense lesion compressing the medulla from the front. The lower limit of the lesion is reaching the fourth cervical vertebra (case 1). B: Sagittal section of the MRI scan (T2-weighted) showing a hyperintense lesion located ventral to brain stem and having the same intensity as that of CSF, indicating it to be an arachnoid cyst (case 1). C: Axial section of the MRI scan at the level of the brain stem showing a large cystic lesion located right anterolateral to the brain stem (case 1).
Fig. 2. A: Sagittal section of the T1-weighted MRI scan showing a hypointense mass lesion located anterior to the brain stem (case 2). B: Sagittal section of the T2-weighted MRI scan showing a large hyperintense cystic lesion anterior to the brain stem. C: Axial section of the T2-weighted MRI scan showing hyperintense cystic lesion anterior and right to the brain stem. The ribbon-shaped compressed brain stem is noteworthy.
S. Mohindra et al. / Surgical Neurology 68 (2007) 85 – 88
was restored. Postoperatively, the patient made an eventless recovery and remains asymptomatic at 2 years follow-up. 3. Case 2 A 9-year-old girl presented with complaints of slowly progressive weakness of all 4 limbs and gait difficulty. She was having difficulty holding fine objects, and there was a change in handwriting. On examination, the child could walk with support (motor power grade 4/5), and all 4 limbs were severely spastic. There were no bladder complaints. Suspecting it to be a case of craniovertebral junction anomaly, plain radiographs were done, which did not reveal any abnormality. Magnetic resonance imaging scan of craniovertebral junction revealed a large cystic lesion ventral to the brain stem, which extends both above and below the foramen magnum, causing posterior displacement and kinking of the brain stem (Fig. 2A-C). There was no hydrocephalus. Fenestration with partial excision of cyst wall was carried out via midline posterior fossa approach. Postoperatively, the child improved rapidly, and normal gait was restored. The patient has remained asymptomatic at 10 years follow-up. 4. Discussion Eight cases of craniovertebral junction arachnoid cysts have been reported up to now [2,3,5,11,15,18,19]. All the reported cases (except one case with a laterally placed cyst) have described dorsally located posterior fossa, infravermian arachnoid cysts, extending into upper cervical canal and pushing the cord anteriorly. All reported cases were adults, except 1 patient aged 16 years (Table 1). The cases reported here are unique because the cysts were located ventrally and the clinical presentation was in the pediatric age group. The presentation of cysts has been attributed to the direct compression of neural structures or
87
interference with CSF circulation. The late presentation in adult age of these congenital cysts is possibly due to relatively slow growth or expansion [15]. Thus, the mean age of diagnosis of reported cysts in the literature was 38 years. The 2 cases reported here presented at the age of 8 and 9 years. We believe that this early presentation was possibly related to the anterior location. Being ventral, there was relatively early interruption of pyramidal pathways leading to clinical presentation in the form of spasticity in childhood, and the imaging diagnosis also tends to be early as these cannot be confused with a large cisterna magna. The differential diagnoses of a cystic lesion at this region are neuroenteric cysts [1,6,12] and developmental dermoid or epidermoid cysts [4,17], which can also present with similar clinical complaints. Diffusion-weighted MRI reveals no water restriction in the case of arachnoid cysts, whereas epidermoid cysts show water restriction [3]. These developmental epidermoid or dermoid cysts also present in the first 2 decades of life, and the associated spina bifida or dermal sinus tract may be an indicator of their presence. Arachnoid cysts have signal intensity identical to that of CSF (Figs. 1A-C and 2A-C). The high intensity on T1weighted and hyperintense signal on T2-weighted MRI images similar to that of CSF helped to diagnose arachnoid cysts in both of our cases. Epidermoid cyst is another important differential diagnosis, as cases of developmental dermoid/epidermoid cysts have been reported at the craniovertebral junction [4]. Commonly developing in the cerebellopontine cistern and parasellar region, these cysts usually have low signal and high signal on T1-weighted and T2-weighted magnetic resonance images, respectively [17]. Diffusion-weighted images show iso-hyperintensity compared with the brain and can be distinguished from other cysts [17]. Neuroenteric cysts at the craniovertebral junction have also been reported [1,6,12]. These are endothelium-lined
Table 1 Summary of craniovertebral junction arachnoid cysts reported in literature Author
Age/Sex
Symptoms
Radiology
Cyst location
Treatment
Follow-up
Outcome
Kuroiwa et al (1991) [11]
59/Male
MRI
Dorsal to brainstem
Partial excision
–
–
Bhatia et al (1992) [2]
22/Male
CT myelogram
Dorsal to brainstem
Partial excision
1 mo
Good
Takanashi et al (1995) [19]
36/Male
CT and MRI
Dorsal to brainstem
Partial excision
–
–
Fukushima et al (1996) [5]
54/Female
MRI
Dorsal to brainstem
Partial excision
1 mo
Good
Shukla et al (1998) [18]
16/Male
Posttraumatic, spastic gait Urinary hesitancy, spastic paraparesis Cerebellar symptoms, right arm dysesthesia Raised ICP, head and neck pain High cord compression
MRI
Dorsal to brainstem
3 wk
Good
Pego-Reigosa et al (2000) [14] Price et al (2001) [15] Cakirer et al (2004) [3]
48/Male
MRI
Dorsal to brain stem
Cystoperitoneal shunt Partial excision
–
–
MRI MRI
Dorsal to brainstem Left of brainstem
Complete excision Partial excision
18 mo –
Good –
Present case
8/Male
MRI
Ventral to brainstem
Partial excision
2y
Good
Present case
9/Female
MRI
Ventral to brainstem
Partial excision
10 y
Good
37/Female 27/Female
Gait problems, spastic paraparesis Raised ICP Head and neck pain, left arm weakness, dysesthesia High cord compression, urinary hesitancy High cord compression
88
S. Mohindra et al. / Surgical Neurology 68 (2007) 85 – 88
resonance imaging scans with T1-, T2-, and diffusionweighted sequences help in diagnosis and in the differentiation from other lesions located at this location. Fenestration with partial cyst wall excision gives good results. References
Fig. 3. Microphotograph showing a collapsed cystic structure lined by arachnoid cells. Multilayering of cells can be seen at places.
cysts located ventrally, and the correct preoperative diagnosis may not always be possible [1]. Diffusion-weighted MRI images of neuroenteric cysts reveal low-signal intensity similar to that seen in the arachnoid cyst. Neuroenteric cysts may be associated with vertebral anomalies such as segmentation fusion defects [9]. Hence, evaluation of bony anatomy and histopathological examination of the lesion are necessary to establish a correct diagnosis (Fig. 3). Primary arachnoid cysts are embryonic malformations due to an error in the differentiation of early endomeningeal tissue [2,13]. Secondary arachnoid cysts may form as a consequence of meningitis, trauma, and hemorrhage [2,13,15]. The progressive expansion of such arachnoid cysts is attributed to ball-valve mechanism between the cyst and the subarachnoid space [7], or active fluid secretion by the cells lining the cyst wall [8]. Fenestration with partial excision of cyst wall remains the surgical treatment of choice [2,15]. Suboccipital craniotomy and laminotomy using drill system can provide good anatomic reconstruction and minimal problems in long-term follow-up, especially among pediatric patients. Both of our patients remain asymptomatic at long-term follow-up. A cystoperitoneal shunt may be needed for a recurrent cyst [15]. 5. Conclusion Arachnoid cysts situated ventral to the brain stem and presenting in the pediatric age group have not been reported previously. These lesions present with spasticity because of compression over the corticospinal tracts. Magnetic
[1] Abe K, Oyama K, Mori K, Ishimaru S, Eguchi M, Maeda M. Neurenteric cyst of the craniocervical junction—case report. Neurol Med Chir (Tokyo) 1999;39:875 - 80. [2] Bhatia S, Thakur RC, Radotra BD, Kak VK. Craniospinal intradural arachnoid cyst. Postgrad Med J 1992;68:829 - 30. [3] Cakirer S. Arachnoid cyst of the craniospinal junction: a case report and review of the literature. Acta Radiol 2004;45:460 - 3. [4] Chandra PS, Gupta A, Mishra NK, Mehta VS. Association of craniovertebral and upper cervical anomalies with dermoid and epidermoid cysts: report of four cases. Neurosurgery 2005;56:1155. [5] Fukushima Y, Sato M, Taguchi J, Sasaki M, Kanai N, Hayakawa T. Craniospinal arachnoid cyst: case report [Article in Japanese]. No Shinkei Geka 1996;24:75 - 9. [6] Fuse T, Yamada K, Kamiya K, Inagaki H. Neurenteric cyst at the craniovertebral junction: report of two cases. Surg Neurol 1998;50: 431 - 6. [7] Galassi E, Tognetti F, Gaist G, Frank F. Arachnoid cysts of the middle cranial fossa; a clinical and radiological study of 25 cases treated surgically. Surg Neurol 1980;14:211 - 9. [8] Go RG, Houthoff HJ, Blaauw EH, Havinga P, Hartsuiker J. Arachnoid cysts of sylvian fissure. Evidence of fluid secretion. J Neurosurg 1984; 60:803 - 13. [9] Kapoor V, Johnson DR, Fukui MB, Rothfus WE, Jho HD. Neuroradiologic-pathologic correlation in a neurenteric cyst of the clivus. AJNR AJNR Am J Neuroradiol 2002476 - 9. [10] Kollias S, Ball WS, Prenger EC. Cystic malformations of the posterior fossa: differential diagnosis clarified through embryologic analysis. Radiographics 19931211 - 31. [11] Kuroiwa T, Takeuchi E, Yamada K, Ohta T, Miyaji Y, Onomura T. An intradural arachnoid cyst of the craniovertebral junction; a case report [Article in Japanese]. No Shinkei Geka 1991;19:1097 - 9. [12] Lazareff JA, Hoil Parra JA. Intradural neurenteric cyst at the craniovertebral junction. Childs Nerv Syst 1995;11:536 - 8. [13] Naidich TP, McLone DG, Radkowski MA. Intracranial arachnoid cysts. Pediatr Neurosci 1985-86;12:112 - 22. [14] Pego-Reigosa R, Branas-Fernandez F, Martinez-Vazquez F, CortesLaino JA. Craniospinal intradural arachnoid cyst. Arch Neurol 2000; 57:128. [15] Price SJ, David KM, O’Donovan DG, Aspoas AR. Arachnoid cyst of the craniocervical junction: case report. Neurosurgery 2001;49:212 - 5. [16] Robinson RG. Congenital cysts of the brain: arachnoid malformations. Prog Neurol Surg 1971;4:133 - 74. [17] Shakudo M, Inoue Y, Ohata K, Tanaka S. Neurenteric cyst with alteration of signal intensity on follow-up MR images. AJNR Am J Neuroradiol 2001;22:496 - 8. [18] Shukla R, Sharma A, Vatsal DK. Posterior fossa arachnoid cyst presenting as high cervical cord compression. Br J Neurosurg 1998; 12:271 - 3. [19] Takanashi Y, Mochimatsu Y, Shyudo T, Yamamoto I. A case report of an arachnoid cyst in the craniovertebral junction [Article in Japanese]. No To Shinkei 1991;47:68 - 70.