British Journal of Neurosurgery
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
Bilateral cerebellopontine arachnoid cyst: A rare entity Anand Sharma, Achal Sharma, Radhey S. Mittal & Ashok Gandhi To cite this article: Anand Sharma, Achal Sharma, Radhey S. Mittal & Ashok Gandhi (2015) Bilateral cerebellopontine arachnoid cyst: A rare entity, British Journal of Neurosurgery, 29:4, 576-578, DOI: 10.3109/02688697.2015.1015100 To link to this article: http://dx.doi.org/10.3109/02688697.2015.1015100
Published online: 27 Mar 2015.
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Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ibjn20 Download by: [University of California Santa Barbara]
Date: 27 October 2015, At: 10:36
British Journal of Neurosurgery, August 2015; 29(4): 576–578 © 2015 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2015.1015100
CASE REPORT
Bilateral cerebellopontine arachnoid cyst: A rare entity Anand Sharma, Achal Sharma, Radhey S. Mittal & Ashok Gandhi
Downloaded by [University of California Santa Barbara] at 10:37 27 October 2015
Department of Neurosurgery, SMS Medical College, Jaipur, India confirmed the presence of bilateral AC on fluid attenuation inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) sequences (Fig. 1B, 1C, 1D, 1E). After discussion of risks and benefits, the patient underwent left retromastoid suboccipital craniectomy and cyst fenestration but soon after decompression of AC patient developed hypotension followed by sudden cardiac arrest. Immediate resuscitation was started; however, the patient could not be revived.
Abstract Bilateral cerebellopontine angle (CPA) arachnoid cysts (ACs) are very rare: only one case is reported in literature. Pathogenesis of those cysts is unknown; they are thought to be congenital. The presenting symptoms of CPA AC are frequently nonspecific or otological. The management of ACs of the CPA is controversial. We are reporting two cases of bilateral CPA AC with their pathophysiology and review of literature.
Case 2
Keywords: arachnoid cyst; bilateral cerebellopontine angle
A five-month-old infant was referred from pediatric department with history of progressive enlargement of head since birth and one-month history of occasional vomiting with altered level of consciousness since one day. On examination, the child was restless and irritable with delayed milestone; her anterior fontanel was markedly bulging and tense with engorgement of the scalp veins. Her head circumference was 43 cm. CT scan revealed extra-axial hypodense lesion in bilateral CPA, extending toward dorsum of brainstem, suprasellar cistern, and compressing brainstem and both cerebellar hemispheres (Fig. 2A). The aqueduct and fourth ventricle were obscured by ACs, causing massive dilation of the third and lateral ventricles with excessive periventricular white matter intensity changes. MRI confirmed the presence of hydrocephalus and bilateral CPA AC on various sequences (Fig. 2B, 2C, 2D). Considering emergency, left ventriculoperitonial shunt was performed (Fig. 2E). The postoperative course was uneventful. On follow-up, overall development of the child improved gradually, achieved neck control within 1 month, and presently at two years of age, her developmental milestones are normal. After discussion of risk and benefits of definitive surgery with their parents, a decision of conservative management was taken by monitoring with serial MRIs.
Introduction Arachnoid cysts (ACs) are benign, rare, intraarachnoid lesion filled with fluid similar to or exactly like cerebrospinal fluid. They are thought to be congenital; or develop secondary to infection, trauma, splitting abnormalities of the arachnoid membrane, alteration of the cerebrospinal fluid (CSF) flow, and/or change in the CSF pressure.1 Cerebellopontine angle (CPA) is a rare site for AC and constitute about 11% of all intracranial AC and 1% of all intracranial mass lesions. Bilateral CPA ACs are very rare and after reviewing the available English literature we could find only one case report.1 We are presenting two cases of bilateral CPA ACs with review of literature.
Case reports Case 1 A 5-year-old girl presented with history of tinnitus in left ear and progressive loss of hearing in both ear for last 2 years and bifrontal headache since 2 month. Initially she was treated by ENT surgeon without any improvement in her complaints. On examination the patient was found to have bilateral profound sensorineural hearing loss without any other neurological deficit. Her audiometric evaluation showed profound sensorineural hearing loss at high frequencies bilaterally and brainstem evoked response audiometry showed absence of I, III, and V latencies. Computed tomography (CT) scan revealed an extra-axial hypodense lesion in bilateral CPA, larger on left side compressing brainstem and left cerebellar hemisphere (Fig. 1A). Magnetic resonance imaging (MRI)
Discussion Bilateral CPA ACs are very rare; their pathogenesis remains unknown. Available literature and their occurrence during the childhood years support their congenital origin. According to one theory, fluid enters the cyst through cyst wall (by means of osmotic pressure gradient) and is retained inside or
Correspondence: Dr. Anand Sharma, Department of Neurosurgery, SMS Medical College, Jaipur, 302004(India). Tel: ⫹ 91-8696351488. E-mail: [email protected] Received for publication 27 April 2014; accepted 20 January 2015
576
Downloaded by [University of California Santa Barbara] at 10:37 27 October 2015
Bilateral cerebellopontine arachnoid cyst 577
Fig. 1. Noncontrast CT image (A) and various sequences T1 (B), T2 (C), Flair (D), DWI (E) of bilateral CPA AC.
CSF flows into the cyst through a ball valve mechanism, and the cyst is consequently enlarged.1 Although it is not clear why the incidence of symptomatic ACs is higher in children, it may be that relative expansion of the cyst during a period of normal growth and development leads to a disproportionately higher risk of increased mass effect and increased intracranial pressure. Later in life, this risk of significant relative growth of the cyst may be greatly reduced, leading to a fairly benign natural history of these lesions in adulthood. CPA ACs are usually asymptomatic but can present with a symptoms of a slowly progressive space-occupying mass lesion in CPA. Stretching or compression of the various nerves can lead to vertigo, tinnitus, and sensorineural hearing loss
or produce hemifacial spasm or trigeminal neuralgia. Larger cyst may distort the adjacent cerebellum, leading to intention tremor, and ataxic gait. Further expansion by the cyst may occlude the aqueduct or fourth ventricle producing hydrocephalus.1 The differential diagnosis of CPA AC includes epidermoid and neurenteric cyst, cystic acoustic schwannomas. MRI is helpful in differentiating ACs from other cystic lesions. On MRI, ACs appear as smooth-surfaced lesions that exhibit a signal characteristic of CSF in all MR sequences (DWI and FLAIR). The management of ACs of the CPA remains controversial. Asymptomatic ACs do not require treatment, and such patients should be monitored clinically and radiologically
Fig. 2. Noncontract CT image of preoperative(A), postoperative (E), and various sequences of MRI T1 (B), T2 (C), FLAIR (D) of bilateral CPA AC.
Downloaded by [University of California Santa Barbara] at 10:37 27 October 2015
578
A. Sharma et al.
with serial MRIs. Symptomatic ACs of the CPA with raised intracranial pressure should be treated by CSF shunting or fenestration.2 We preferred ventriculoperitonial shunt over fenestration as an initial procedure. This approach had been supported by various other studies2 included 42 patients of intracranial AC with macrocephaly and they concluded that better results have been demonstrated when VP shunt insertion precedes cyst fenestration. Various other surgical procedures including total resection and drainage, cystoperitonial shunt, and marsupialization can also be used. Stereotactic puncture and endoscopy fenestration have also been successfully employed in the treatment of AC. Endoscopic management has less surgical morbidity than open procedure, and has been shown to be a safe and effective modality for treating AC. Surgical treatment frequently improves vestibular symptoms but auditory deficits are less likely to respond to surgery.1–3 Major complications of open surgery include cranial nerve deficit, hemiparesis, subdural hematomas, and even sudden death. Cause of death in the first case is not clear; it might be due to reperfusion injury, implying that there was increased intracranial pressure before cyst drainage. Other possible pathogenetic mechanisms of this complication are abrupt change in blood circulation, faulty autoregulation, and brain decompression as the cause of superficial veins distortion.3 reported seven cases of intracranial hematomas after drainage of extracerebral collections (5% in their series), this might be due to i) focal edema in the compressed brain; ii) reduction of venous return at the affected side; iii) subcortical swelling in the compressed area; and iv) reduction of the regional blood
flow in the ipsilateral hemisphere in cases of chronic subdural hematoma. The sudden decompression could cause edema and bleeding as it might have happened in our case. Reevaluation of the clinical case would permit us to believe that in such cases more gradual decompression through indirect surgical approach with programmable shunts or simple tapping would permit a slower decompression of the intracranial structures and consequently readaptation of the microcirculation to the circumstantial perfusion pressure. In conclusion, bilateral AC of CPA is very rare clinical entity with poorly defined etiology and pathogenesis. It becomes even more challenging when more uncertainties exist regarding rare bilateral AC operations. Direct surgical approach may cause serious complications. Gradual decompression through indirect surgical approach may emerge as a better option with less probable mortality. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References 1. Ucar T, Akyuz M, Kazan S, Tuncer R. Bilateral cerebellopontine angle arachnoid cysts: case report. Neurosurgery 2000;47:966–8. 2. Zada G, Krieger MD, McNatt SA , Bowen I, McComb JG. Pathogenesis and treatment of intracranial arachnoid cysts in pediatric patients younger than 2 years of age. Neurosurg Focus 2007;22: E1. 3. Modesti L, Hodge CJ, Barmwell ML. Intracerebral hematoma after evacuation of chronic extracerebral fluid collections. Neurosurgery 1982;10:689–93.
ISSN: 0268-8697 (Print) 1360-046X (Online) Journal homepage: http://www.tandfonline.com/loi/ibjn20
Bilateral cerebellopontine arachnoid cyst: A rare entity Anand Sharma, Achal Sharma, Radhey S. Mittal & Ashok Gandhi To cite this article: Anand Sharma, Achal Sharma, Radhey S. Mittal & Ashok Gandhi (2015) Bilateral cerebellopontine arachnoid cyst: A rare entity, British Journal of Neurosurgery, 29:4, 576-578, DOI: 10.3109/02688697.2015.1015100 To link to this article: http://dx.doi.org/10.3109/02688697.2015.1015100
Published online: 27 Mar 2015.
Submit your article to this journal
Article views: 19
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ibjn20 Download by: [University of California Santa Barbara]
Date: 27 October 2015, At: 10:36
British Journal of Neurosurgery, August 2015; 29(4): 576–578 © 2015 The Neurosurgical Foundation ISSN: 0268-8697 print / ISSN 1360-046X online DOI: 10.3109/02688697.2015.1015100
CASE REPORT
Bilateral cerebellopontine arachnoid cyst: A rare entity Anand Sharma, Achal Sharma, Radhey S. Mittal & Ashok Gandhi
Downloaded by [University of California Santa Barbara] at 10:37 27 October 2015
Department of Neurosurgery, SMS Medical College, Jaipur, India confirmed the presence of bilateral AC on fluid attenuation inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) sequences (Fig. 1B, 1C, 1D, 1E). After discussion of risks and benefits, the patient underwent left retromastoid suboccipital craniectomy and cyst fenestration but soon after decompression of AC patient developed hypotension followed by sudden cardiac arrest. Immediate resuscitation was started; however, the patient could not be revived.
Abstract Bilateral cerebellopontine angle (CPA) arachnoid cysts (ACs) are very rare: only one case is reported in literature. Pathogenesis of those cysts is unknown; they are thought to be congenital. The presenting symptoms of CPA AC are frequently nonspecific or otological. The management of ACs of the CPA is controversial. We are reporting two cases of bilateral CPA AC with their pathophysiology and review of literature.
Case 2
Keywords: arachnoid cyst; bilateral cerebellopontine angle
A five-month-old infant was referred from pediatric department with history of progressive enlargement of head since birth and one-month history of occasional vomiting with altered level of consciousness since one day. On examination, the child was restless and irritable with delayed milestone; her anterior fontanel was markedly bulging and tense with engorgement of the scalp veins. Her head circumference was 43 cm. CT scan revealed extra-axial hypodense lesion in bilateral CPA, extending toward dorsum of brainstem, suprasellar cistern, and compressing brainstem and both cerebellar hemispheres (Fig. 2A). The aqueduct and fourth ventricle were obscured by ACs, causing massive dilation of the third and lateral ventricles with excessive periventricular white matter intensity changes. MRI confirmed the presence of hydrocephalus and bilateral CPA AC on various sequences (Fig. 2B, 2C, 2D). Considering emergency, left ventriculoperitonial shunt was performed (Fig. 2E). The postoperative course was uneventful. On follow-up, overall development of the child improved gradually, achieved neck control within 1 month, and presently at two years of age, her developmental milestones are normal. After discussion of risk and benefits of definitive surgery with their parents, a decision of conservative management was taken by monitoring with serial MRIs.
Introduction Arachnoid cysts (ACs) are benign, rare, intraarachnoid lesion filled with fluid similar to or exactly like cerebrospinal fluid. They are thought to be congenital; or develop secondary to infection, trauma, splitting abnormalities of the arachnoid membrane, alteration of the cerebrospinal fluid (CSF) flow, and/or change in the CSF pressure.1 Cerebellopontine angle (CPA) is a rare site for AC and constitute about 11% of all intracranial AC and 1% of all intracranial mass lesions. Bilateral CPA ACs are very rare and after reviewing the available English literature we could find only one case report.1 We are presenting two cases of bilateral CPA ACs with review of literature.
Case reports Case 1 A 5-year-old girl presented with history of tinnitus in left ear and progressive loss of hearing in both ear for last 2 years and bifrontal headache since 2 month. Initially she was treated by ENT surgeon without any improvement in her complaints. On examination the patient was found to have bilateral profound sensorineural hearing loss without any other neurological deficit. Her audiometric evaluation showed profound sensorineural hearing loss at high frequencies bilaterally and brainstem evoked response audiometry showed absence of I, III, and V latencies. Computed tomography (CT) scan revealed an extra-axial hypodense lesion in bilateral CPA, larger on left side compressing brainstem and left cerebellar hemisphere (Fig. 1A). Magnetic resonance imaging (MRI)
Discussion Bilateral CPA ACs are very rare; their pathogenesis remains unknown. Available literature and their occurrence during the childhood years support their congenital origin. According to one theory, fluid enters the cyst through cyst wall (by means of osmotic pressure gradient) and is retained inside or
Correspondence: Dr. Anand Sharma, Department of Neurosurgery, SMS Medical College, Jaipur, 302004(India). Tel: ⫹ 91-8696351488. E-mail: [email protected] Received for publication 27 April 2014; accepted 20 January 2015
576
Downloaded by [University of California Santa Barbara] at 10:37 27 October 2015
Bilateral cerebellopontine arachnoid cyst 577
Fig. 1. Noncontrast CT image (A) and various sequences T1 (B), T2 (C), Flair (D), DWI (E) of bilateral CPA AC.
CSF flows into the cyst through a ball valve mechanism, and the cyst is consequently enlarged.1 Although it is not clear why the incidence of symptomatic ACs is higher in children, it may be that relative expansion of the cyst during a period of normal growth and development leads to a disproportionately higher risk of increased mass effect and increased intracranial pressure. Later in life, this risk of significant relative growth of the cyst may be greatly reduced, leading to a fairly benign natural history of these lesions in adulthood. CPA ACs are usually asymptomatic but can present with a symptoms of a slowly progressive space-occupying mass lesion in CPA. Stretching or compression of the various nerves can lead to vertigo, tinnitus, and sensorineural hearing loss
or produce hemifacial spasm or trigeminal neuralgia. Larger cyst may distort the adjacent cerebellum, leading to intention tremor, and ataxic gait. Further expansion by the cyst may occlude the aqueduct or fourth ventricle producing hydrocephalus.1 The differential diagnosis of CPA AC includes epidermoid and neurenteric cyst, cystic acoustic schwannomas. MRI is helpful in differentiating ACs from other cystic lesions. On MRI, ACs appear as smooth-surfaced lesions that exhibit a signal characteristic of CSF in all MR sequences (DWI and FLAIR). The management of ACs of the CPA remains controversial. Asymptomatic ACs do not require treatment, and such patients should be monitored clinically and radiologically
Fig. 2. Noncontract CT image of preoperative(A), postoperative (E), and various sequences of MRI T1 (B), T2 (C), FLAIR (D) of bilateral CPA AC.
Downloaded by [University of California Santa Barbara] at 10:37 27 October 2015
578
A. Sharma et al.
with serial MRIs. Symptomatic ACs of the CPA with raised intracranial pressure should be treated by CSF shunting or fenestration.2 We preferred ventriculoperitonial shunt over fenestration as an initial procedure. This approach had been supported by various other studies2 included 42 patients of intracranial AC with macrocephaly and they concluded that better results have been demonstrated when VP shunt insertion precedes cyst fenestration. Various other surgical procedures including total resection and drainage, cystoperitonial shunt, and marsupialization can also be used. Stereotactic puncture and endoscopy fenestration have also been successfully employed in the treatment of AC. Endoscopic management has less surgical morbidity than open procedure, and has been shown to be a safe and effective modality for treating AC. Surgical treatment frequently improves vestibular symptoms but auditory deficits are less likely to respond to surgery.1–3 Major complications of open surgery include cranial nerve deficit, hemiparesis, subdural hematomas, and even sudden death. Cause of death in the first case is not clear; it might be due to reperfusion injury, implying that there was increased intracranial pressure before cyst drainage. Other possible pathogenetic mechanisms of this complication are abrupt change in blood circulation, faulty autoregulation, and brain decompression as the cause of superficial veins distortion.3 reported seven cases of intracranial hematomas after drainage of extracerebral collections (5% in their series), this might be due to i) focal edema in the compressed brain; ii) reduction of venous return at the affected side; iii) subcortical swelling in the compressed area; and iv) reduction of the regional blood
flow in the ipsilateral hemisphere in cases of chronic subdural hematoma. The sudden decompression could cause edema and bleeding as it might have happened in our case. Reevaluation of the clinical case would permit us to believe that in such cases more gradual decompression through indirect surgical approach with programmable shunts or simple tapping would permit a slower decompression of the intracranial structures and consequently readaptation of the microcirculation to the circumstantial perfusion pressure. In conclusion, bilateral AC of CPA is very rare clinical entity with poorly defined etiology and pathogenesis. It becomes even more challenging when more uncertainties exist regarding rare bilateral AC operations. Direct surgical approach may cause serious complications. Gradual decompression through indirect surgical approach may emerge as a better option with less probable mortality. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
References 1. Ucar T, Akyuz M, Kazan S, Tuncer R. Bilateral cerebellopontine angle arachnoid cysts: case report. Neurosurgery 2000;47:966–8. 2. Zada G, Krieger MD, McNatt SA , Bowen I, McComb JG. Pathogenesis and treatment of intracranial arachnoid cysts in pediatric patients younger than 2 years of age. Neurosurg Focus 2007;22: E1. 3. Modesti L, Hodge CJ, Barmwell ML. Intracerebral hematoma after evacuation of chronic extracerebral fluid collections. Neurosurgery 1982;10:689–93.
