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Iatrogenic postoperative cerebellar cyst
Journal of Clinical Neuroscience xxx (2016) xxx–xxx
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Case report
Iatrogenic postoperative cerebellar cyst Robin Sharif a, Samuel Moscovici a,⇑, Marc Wygoda b, Ruth Eliahou c, Sergey Spektor a a
Department of Neurosurgery, Hadassah-Hebrew University Medical Center, P.O. Box 12000, Jerusalem 91120, Israel Department of Oncology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel c Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel b
a r t i c l e
i n f o
Article history: Received 19 May 2016 Accepted 25 May 2016 Available online xxxx Keywords: Cerebellar cyst Iatrogenic Postoperative complication Vestibular schwannoma
a b s t r a c t Cerebellar cyst is a known but uncommon entity. It is congenital in most cases, or may develop after brain parenchyma injuries or interventions. To our knowledge, de novo cerebellar cyst after extra-axial tumor excision, has not been described in the literature. We present the first reported case of a de novo cerebellar cyst developing in a 70-year-old woman following retrosigmoid craniotomy for vestibular schwannoma excision, and discuss the possible causes. Following cyst fenestration, there was no clinical or radiological evidence of a residual cyst. Ó 2016 Elsevier Ltd. All rights reserved.
1. Introduction Simple cerebellar cysts are uncommon [1]. Most cerebellar cysts are congenital with syndromatic associations (for example, arachnoid cyst, Dandy-Walker cyst), or intracerebellar colloid cysts [2], cysts associated with ganglioglioma [3], simple cysts [1], or cysts that develop following stereotactic radiosurgery (SRS) for the treatment of arteriovenous malformation (AVM) [4]. We found only one report of a simple cerebellar cyst that developed following craniotomy via supracerebellar infratentorial approach for treatment of a pineal cyst [5]. We present a case of iatrogenic cerebellar cyst that developed following retrosigmoid craniotomy for vestibular schwannoma excision, and discuss the possible causes.
2. Case report A 70-year-old woman known to have idiopathic chronic cough, presented with a 4-month history of dizziness and progressive left hearing loss. She was diagnosed with a small left vestibular schwannoma. At 2-year follow-up, the cyst had increased in size (2.1 cc). The patient underwent SRS (single-dose, 12 Gy to the encompassing 80% isodose line, 15 Gy maximal dose). On 3-year follow-up MRI, the tumor had enlarged, with signs of perilesional edema and brainstem pressure. The patient complained of hemifacial spasm and left deafness. ⇑ Corresponding author. Tel.: +972 50 894 6973. E-mail address: [email protected] (S. Moscovici).
The patient underwent tumor excision via a retrosigmoidal approach. The surgery was unremarkable, with cerebrospinal fluid (CSF) release from the cisterna magna, gentle cerebellar retraction and microsurgical dissection. Most of the tumor was removed, including a segment in the internal canal, leaving a small (5 7 mm) residual adherent to the facial nerve in the ventralpremeatal area. On closure, the cerebellar hemisphere looked normal. There were no complications. The patient’s hemifacial spasm resolved, and facial function was normal (House-Brackmann 1). Postoperative head CT scan showed good resection with no signs of significant bleeding or hydrocephalus (Fig. 1A). She was discharged to inpatient rehabilitation due to dizziness and unstable gait. After initial improvement, she regressed, with increased ataxia and coordination problems, 1 month after surgery. She stopped walking and developed a strong headache and vomiting, without papilledema. MRI showed a round 22 27 mm lesion in the left cerebellum that was hypointense on T1-weighted MRI and hyperintense on T2-weighted MRI, with no restriction in the diffusionweighted imaging protocol (DWI-MRI), without hydrocephalus, compatible with intracerebellar cyst (Fig. 1B). Lumbar continuous drainage for 5 days did not alleviate her symptoms; thus, the patient underwent a re-craniotomy. The surgical wound was opened. Under the surgical microscope, a small (pinpoint) hole on the inferior cortical surface of the cerebellum (Fig. 2A) was gently expanded with forceps, and a cavity inside the cerebellar hemisphere containing CSF was inspected (Fig. 2B). There was no capsule, no other communicating openings were found, and no evidence of infection was seen. A small corticectomy
http://dx.doi.org/10.1016/j.jocn.2016.05.019 0967-5868/Ó 2016 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Sharif R et al. Iatrogenic postoperative cerebellar cyst. J Clin Neurosci (2016), http://dx.doi.org/10.1016/j. jocn.2016.05.019
2
Case Report / Journal of Clinical Neuroscience xxx (2016) xxx–xxx
Fig. 1. (A) Postoperative unenhanced axial head CT scan demonstrating wide resection of a left vestibular schwannoma in a 70-year-old woman. (B) The patient deteriorated 1 month after surgery, with increased ataxia and coordination problems. Axial T2-weighted MRI showing a 26 mm cystic lesion in the left cerebellum with surrounding edema.
Fig. 2. (A) A small (pinpoint) hole (arrow) is seen in the inferior cortical surface of the cerebellum. (B) A cavity containing cerebrospinal fluid, inside the cerebellar hemisphere.
Please cite this article in press as: Sharif R et al. Iatrogenic postoperative cerebellar cyst. J Clin Neurosci (2016), http://dx.doi.org/10.1016/j. jocn.2016.05.019
Case Report / Journal of Clinical Neuroscience xxx (2016) xxx–xxx
Fig. 3. T2-weighted MRI shows good fenestration of the cyst.
of the cerebellum in the basal area was performed to provide clear communication between the intracerebellar cyst and the cistern magna. There were no complications. The patient gradually improved. Neurological examination at 2-month follow-up was unremarkable except for minimal ataxia and left ear deafness. MRI demonstrated minimal postoperative changes and a tract in the lower cerebellar hemisphere surface from the minimal residual cystic area in the direction of the cistern magna (Fig. 3).
3
Wait and Spetzler, et al. [5] reported a case of simple cerebellar cyst that developed following removal of a pineal cyst via supracerebellar infratentorial approach. The authors hypothesized that posteroperative changes in venous drainage related to ligation of the large occipital sinus in concert with CSF flow from lumboperitoneal shunting, may be involved in its development. We hypothesize that the cyst in our patient stemmed from a dural defect created in the first steps of the retrosigmoid approach, or a small arachnoidal/parenchymal tear during gentle cerebellar retraction exerted to facilitate tumor removal. The tear may have acted like a unidirectional valve to permit CSF accumulation in cerebellar parenchyma previously exposed to high-dose radiation during SRS treatment. As a result, continuous drainage did not provide a channel for CSF flow into the ventricular system, and fenestration was required to ameliorate the patient’s neurological deterioration. CSF pulsatility may have strong effects, as seen in reports of growing fractures following mild head trauma [9,10]. This water hammer effect could also cause tissue dissection and cyst formation, as well as a valve effect that could prevent spontaneous cyst drainage and lead to a mass effect and swelling. Moreover, our patient continued to cough persistently after the surgery, which most probably enhanced the water hammer effect that may have caused cyst formation. Iatrogenic cyst formation is a very unusual surgical complication. We can only speculate whether increased fragility of the cerebellum following SRS may have facilitated its formation. The potential for cyst formation should be kept in mind in cases of delayed neurological deterioration following craniotomy. Conflicts of Interest/Disclosures The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication. We thank Shifra Fraifeld, a senior medical writer at our Medical Center, for her editorial assistance.
3. Discussion References Intracranial cysts have been reported following radiation therapy [6], placement of bis-chloroethylnitrosourea (BCNU) wafers in the tumor resection cavity in patients with gliomas [7], following radiation-based and chemotherapeutic treatment for gliomas [8], and after gamma knife radiosurgery (GKRS) treatment for parietal AVM [4]; however, none of these reports are similar to our case. The etiology of cerebellar cyst formation is unclear. Edmister et al. [6] proposed that cerebral cyst development after radiation-based treatment for AVM may occur after intraparenchymal hemorrhage, as part of the resolution of the hematoma bed. Volk and colleagues [8] hypothesized that cerebral cysts forming after radiation and chemotherapy for gliomas, may result from CSF accumulation in a noncommunicating cavity or, more frequently, from enhanced tumor necrosis and accumulation of degeneration products in the tumor resection cavity. McGirt et al. [7] suggested that cysts forming after postoperative treatment with BCNU wafers may result from an inflammatory response to the wafer itself. However, in each of these cases, the cyst developed in the same location as the lesion, whereas in our patient, the cyst was ipsilateral, but in a different location from the vestibular schwannoma.
[1] Sugita S, Sugita Y, Honda E, et al. Benign intracerebellar cyst without epithelial lining. Kurume Med J 1994;41:199–204. [2] Müller A, Büttner A, Weis S. Rare occurrence of intracerebellar colloid cyst. Case report. J Neurosurg 1999;91:128–31. [3] Tokunaga H, Sunami K, Wagai N, et al. Ganglioglioma originating in the cerebellum with a large cyst–a case report and review of the literature. Clin Neuropathol 2008;27:369–72. [4] Kim MS, Lee SI, Sim JH. A case of very large cyst formation with Gamma Knife radiosurgery for an arteriovenous malformation. Stereotact Funct Neurosurg 1999;72:168–74. [5] Wait SD, Felz-Erfan I, Hanel RA, et al. De novo postoperative simple cerebellar cyst. Barrow Quart 2006;22:15–6. [6] Edmister WB, Lane JI, Gilbertson JR, et al. Tumefactive cysts: a delayed complication following radiosurgery for cerebral arterial venous malformations. Am J Neuroradiol 2005;26:1152–7. [7] McGirt MJ, Villavicencio AT, Bulsara KR, et al. Management of tumor bed cysts after chemotherapeutic wafer implantation. Report of four cases. J Neurosurg 2002;96:941–5. [8] Volc D, Jellinger K, Flament H, et al. Cerebral space-occupying cysts following radiation and chemotherapy of malignant gliomas. Acta Neurochir (Wien) 1981;57:177–93. [9] Kulkarni K, Pandya N, Hulse T. Leptomeningeal cysts: a complication of trivial head injury. Internet J Pediatr Neonatol 2008;9. Available from: http:// ispub.com/IJPN/9/2/8351. [Accessed May 9, 2016]. [10] Sato O, Tsugane R, Kageyama N. Growing skull fractures of childhood. Possible mechanism of its focal ventricular dilatation. Childs Brain 1975;1:148–57.
Please cite this article in press as: Sharif R et al. Iatrogenic postoperative cerebellar cyst. J Clin Neurosci (2016), http://dx.doi.org/10.1016/j. jocn.2016.05.019
Contents lists available at ScienceDirect
Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn
Case report
Iatrogenic postoperative cerebellar cyst Robin Sharif a, Samuel Moscovici a,⇑, Marc Wygoda b, Ruth Eliahou c, Sergey Spektor a a
Department of Neurosurgery, Hadassah-Hebrew University Medical Center, P.O. Box 12000, Jerusalem 91120, Israel Department of Oncology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel c Department of Radiology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel b
a r t i c l e
i n f o
Article history: Received 19 May 2016 Accepted 25 May 2016 Available online xxxx Keywords: Cerebellar cyst Iatrogenic Postoperative complication Vestibular schwannoma
a b s t r a c t Cerebellar cyst is a known but uncommon entity. It is congenital in most cases, or may develop after brain parenchyma injuries or interventions. To our knowledge, de novo cerebellar cyst after extra-axial tumor excision, has not been described in the literature. We present the first reported case of a de novo cerebellar cyst developing in a 70-year-old woman following retrosigmoid craniotomy for vestibular schwannoma excision, and discuss the possible causes. Following cyst fenestration, there was no clinical or radiological evidence of a residual cyst. Ó 2016 Elsevier Ltd. All rights reserved.
1. Introduction Simple cerebellar cysts are uncommon [1]. Most cerebellar cysts are congenital with syndromatic associations (for example, arachnoid cyst, Dandy-Walker cyst), or intracerebellar colloid cysts [2], cysts associated with ganglioglioma [3], simple cysts [1], or cysts that develop following stereotactic radiosurgery (SRS) for the treatment of arteriovenous malformation (AVM) [4]. We found only one report of a simple cerebellar cyst that developed following craniotomy via supracerebellar infratentorial approach for treatment of a pineal cyst [5]. We present a case of iatrogenic cerebellar cyst that developed following retrosigmoid craniotomy for vestibular schwannoma excision, and discuss the possible causes.
2. Case report A 70-year-old woman known to have idiopathic chronic cough, presented with a 4-month history of dizziness and progressive left hearing loss. She was diagnosed with a small left vestibular schwannoma. At 2-year follow-up, the cyst had increased in size (2.1 cc). The patient underwent SRS (single-dose, 12 Gy to the encompassing 80% isodose line, 15 Gy maximal dose). On 3-year follow-up MRI, the tumor had enlarged, with signs of perilesional edema and brainstem pressure. The patient complained of hemifacial spasm and left deafness. ⇑ Corresponding author. Tel.: +972 50 894 6973. E-mail address: [email protected] (S. Moscovici).
The patient underwent tumor excision via a retrosigmoidal approach. The surgery was unremarkable, with cerebrospinal fluid (CSF) release from the cisterna magna, gentle cerebellar retraction and microsurgical dissection. Most of the tumor was removed, including a segment in the internal canal, leaving a small (5 7 mm) residual adherent to the facial nerve in the ventralpremeatal area. On closure, the cerebellar hemisphere looked normal. There were no complications. The patient’s hemifacial spasm resolved, and facial function was normal (House-Brackmann 1). Postoperative head CT scan showed good resection with no signs of significant bleeding or hydrocephalus (Fig. 1A). She was discharged to inpatient rehabilitation due to dizziness and unstable gait. After initial improvement, she regressed, with increased ataxia and coordination problems, 1 month after surgery. She stopped walking and developed a strong headache and vomiting, without papilledema. MRI showed a round 22 27 mm lesion in the left cerebellum that was hypointense on T1-weighted MRI and hyperintense on T2-weighted MRI, with no restriction in the diffusionweighted imaging protocol (DWI-MRI), without hydrocephalus, compatible with intracerebellar cyst (Fig. 1B). Lumbar continuous drainage for 5 days did not alleviate her symptoms; thus, the patient underwent a re-craniotomy. The surgical wound was opened. Under the surgical microscope, a small (pinpoint) hole on the inferior cortical surface of the cerebellum (Fig. 2A) was gently expanded with forceps, and a cavity inside the cerebellar hemisphere containing CSF was inspected (Fig. 2B). There was no capsule, no other communicating openings were found, and no evidence of infection was seen. A small corticectomy
http://dx.doi.org/10.1016/j.jocn.2016.05.019 0967-5868/Ó 2016 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Sharif R et al. Iatrogenic postoperative cerebellar cyst. J Clin Neurosci (2016), http://dx.doi.org/10.1016/j. jocn.2016.05.019
2
Case Report / Journal of Clinical Neuroscience xxx (2016) xxx–xxx
Fig. 1. (A) Postoperative unenhanced axial head CT scan demonstrating wide resection of a left vestibular schwannoma in a 70-year-old woman. (B) The patient deteriorated 1 month after surgery, with increased ataxia and coordination problems. Axial T2-weighted MRI showing a 26 mm cystic lesion in the left cerebellum with surrounding edema.
Fig. 2. (A) A small (pinpoint) hole (arrow) is seen in the inferior cortical surface of the cerebellum. (B) A cavity containing cerebrospinal fluid, inside the cerebellar hemisphere.
Please cite this article in press as: Sharif R et al. Iatrogenic postoperative cerebellar cyst. J Clin Neurosci (2016), http://dx.doi.org/10.1016/j. jocn.2016.05.019
Case Report / Journal of Clinical Neuroscience xxx (2016) xxx–xxx
Fig. 3. T2-weighted MRI shows good fenestration of the cyst.
of the cerebellum in the basal area was performed to provide clear communication between the intracerebellar cyst and the cistern magna. There were no complications. The patient gradually improved. Neurological examination at 2-month follow-up was unremarkable except for minimal ataxia and left ear deafness. MRI demonstrated minimal postoperative changes and a tract in the lower cerebellar hemisphere surface from the minimal residual cystic area in the direction of the cistern magna (Fig. 3).
3
Wait and Spetzler, et al. [5] reported a case of simple cerebellar cyst that developed following removal of a pineal cyst via supracerebellar infratentorial approach. The authors hypothesized that posteroperative changes in venous drainage related to ligation of the large occipital sinus in concert with CSF flow from lumboperitoneal shunting, may be involved in its development. We hypothesize that the cyst in our patient stemmed from a dural defect created in the first steps of the retrosigmoid approach, or a small arachnoidal/parenchymal tear during gentle cerebellar retraction exerted to facilitate tumor removal. The tear may have acted like a unidirectional valve to permit CSF accumulation in cerebellar parenchyma previously exposed to high-dose radiation during SRS treatment. As a result, continuous drainage did not provide a channel for CSF flow into the ventricular system, and fenestration was required to ameliorate the patient’s neurological deterioration. CSF pulsatility may have strong effects, as seen in reports of growing fractures following mild head trauma [9,10]. This water hammer effect could also cause tissue dissection and cyst formation, as well as a valve effect that could prevent spontaneous cyst drainage and lead to a mass effect and swelling. Moreover, our patient continued to cough persistently after the surgery, which most probably enhanced the water hammer effect that may have caused cyst formation. Iatrogenic cyst formation is a very unusual surgical complication. We can only speculate whether increased fragility of the cerebellum following SRS may have facilitated its formation. The potential for cyst formation should be kept in mind in cases of delayed neurological deterioration following craniotomy. Conflicts of Interest/Disclosures The authors declare that they have no financial or other conflicts of interest in relation to this research and its publication. We thank Shifra Fraifeld, a senior medical writer at our Medical Center, for her editorial assistance.
3. Discussion References Intracranial cysts have been reported following radiation therapy [6], placement of bis-chloroethylnitrosourea (BCNU) wafers in the tumor resection cavity in patients with gliomas [7], following radiation-based and chemotherapeutic treatment for gliomas [8], and after gamma knife radiosurgery (GKRS) treatment for parietal AVM [4]; however, none of these reports are similar to our case. The etiology of cerebellar cyst formation is unclear. Edmister et al. [6] proposed that cerebral cyst development after radiation-based treatment for AVM may occur after intraparenchymal hemorrhage, as part of the resolution of the hematoma bed. Volk and colleagues [8] hypothesized that cerebral cysts forming after radiation and chemotherapy for gliomas, may result from CSF accumulation in a noncommunicating cavity or, more frequently, from enhanced tumor necrosis and accumulation of degeneration products in the tumor resection cavity. McGirt et al. [7] suggested that cysts forming after postoperative treatment with BCNU wafers may result from an inflammatory response to the wafer itself. However, in each of these cases, the cyst developed in the same location as the lesion, whereas in our patient, the cyst was ipsilateral, but in a different location from the vestibular schwannoma.
[1] Sugita S, Sugita Y, Honda E, et al. Benign intracerebellar cyst without epithelial lining. Kurume Med J 1994;41:199–204. [2] Müller A, Büttner A, Weis S. Rare occurrence of intracerebellar colloid cyst. Case report. J Neurosurg 1999;91:128–31. [3] Tokunaga H, Sunami K, Wagai N, et al. Ganglioglioma originating in the cerebellum with a large cyst–a case report and review of the literature. Clin Neuropathol 2008;27:369–72. [4] Kim MS, Lee SI, Sim JH. A case of very large cyst formation with Gamma Knife radiosurgery for an arteriovenous malformation. Stereotact Funct Neurosurg 1999;72:168–74. [5] Wait SD, Felz-Erfan I, Hanel RA, et al. De novo postoperative simple cerebellar cyst. Barrow Quart 2006;22:15–6. [6] Edmister WB, Lane JI, Gilbertson JR, et al. Tumefactive cysts: a delayed complication following radiosurgery for cerebral arterial venous malformations. Am J Neuroradiol 2005;26:1152–7. [7] McGirt MJ, Villavicencio AT, Bulsara KR, et al. Management of tumor bed cysts after chemotherapeutic wafer implantation. Report of four cases. J Neurosurg 2002;96:941–5. [8] Volc D, Jellinger K, Flament H, et al. Cerebral space-occupying cysts following radiation and chemotherapy of malignant gliomas. Acta Neurochir (Wien) 1981;57:177–93. [9] Kulkarni K, Pandya N, Hulse T. Leptomeningeal cysts: a complication of trivial head injury. Internet J Pediatr Neonatol 2008;9. Available from: http:// ispub.com/IJPN/9/2/8351. [Accessed May 9, 2016]. [10] Sato O, Tsugane R, Kageyama N. Growing skull fractures of childhood. Possible mechanism of its focal ventricular dilatation. Childs Brain 1975;1:148–57.
Please cite this article in press as: Sharif R et al. Iatrogenic postoperative cerebellar cyst. J Clin Neurosci (2016), http://dx.doi.org/10.1016/j. jocn.2016.05.019