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Spinal intramedullary ependymal cyst: a case report
Spinal Intramedullary Ependymal Cyst: A Case Report Hideaki Iwahashi, M.D., Shozo Kawai, M.D., Yasuharu Watabe, M.D., Shiro Chitoku, M.D., Nobuhisa Akita, M.D., Takeshi Fuji, M.D.,* and Takenori Oda, M.D.* Departments of Neurosurgery and *Orthopedic Surgery, Osaka Prefectural Hospital, Osaka, Japan
Iwahashi H, Kawai S, Watabe Y, Chitoku S, Akita N, Fuji T, Oda T. Spinal intramedullary ependymal cyst: a case report. Surg Neurol 1999;52:357– 61. BACKGROUND
Spinal intramedullary ependymal cysts are extremely rare. Only seven pathologically proven cases have been reported in the literature. METHOD
We present an 18-month-old female with thoracic spinal intramedullary ependymal cyst that was diagnosed pathologically. RESULTS
Histological diagnosis was made by light microscopy after immunostaining. After partially removing the cyst wall and establishing communication between the cyst and the subarachnoid space, the patient improved neurologically. CONCLUSIONS
For spinal intramedullary ependymal cyst we recommend diagnosis by MR imaging without myelography, then enucleation of the cyst, if possible. Otherwise, we remove the cyst wall as much as possible and create adequate communication between the cyst and the subarachnoid space. © 1999 by Elsevier Science Inc. KEY WORDS
Intramedullary ependymal cyst, spinal cord.
pinal intramedullary ependymal cysts are extremely rare; only seven pathologically proven cases have been reported in the literature. We report here a patient with a spinal intramedullary ependymal cyst and discuss the pathological findings, pathogenesis, nature, and surgical management.
S
Address reprint requests to: Dr Hideaki Iwahashi, Department of Neurosurgery, Osaka Prefectural Hospital, 3-1-56 Bandaihigashi, Sumiyoshiku, Osaka, 558-8558 Japan. Received November 24, 1998; accepted January 25, 1999. © 1999 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
Case Report An 18-month-old female who could not stand up by herself was admitted to our hospital on April 9, 1997. She had been able to walk by herself at 10 months old, but motor weakness of the lower extremities developed at 1 year and 5 months old. Neurological examination on admission revealed a moderate paraparesis, with slightly exaggerated deep tendon jerks and extensor plantar (Babinski) response. Response to pain was dull. Spinal X-ray did not demonstrate any abnormal findings. MR imaging demonstrated a well defined intramedullary mass at the T6 level. The lesion was iso-intense to cerebrospinal fluid and demonstrated low intensity on T1-weighted images (Figure 1A) and high intensity on T2-weighted images (Figure 1B). After administration of Gd-DTPA there was no enhancement of the lesion on MR images (Figure 2). On April 16, 1997, T5-6 laminectomy was performed. Intradural exploration revealed a widened spinal cord without thickness or adhesion to the arachnoid membrane. The cord was swollen at the T6 level and a 7 mm midline myelotomy was performed at this portion. The cyst fluid was clear and colorless. The cyst wall was removed partially. Adequate communication was created between the cyst and the subarachnoid space. The cyst fluid protein concentration was 131 mg/dl. Histopathological study of the surgical specimens revealed that the cyst wall consisted of flattened cuboidal cells and and the underlying stroma was glial. There was no basement membrane seen (Figure 3). These lining cells lacked periodic acid-Schiff(PAS), alacian blue and muciacarmine positivity. Postoperative MR imaging showed a persistent but reduced cyst in the anterior portion of the spinal cord (Figure 4). After surgery, motor weakness and response to pain of the lower extremities grad0090-3019/99/$–see front matter PII S0090-3019(99)00097-X
358 Surg Neurol 1999;52:357–61
1
Iwahashi et al
Preoperative magnetic resonance images: Sagittal T1-weighted (A) and T2-weighted images (B) show an intramedullary cystic lesion at the T6 level.
ually improved. One month postoperatively the patient did not demonstrate any motor weakness and could walk by herself. The patient exhibited no neurological deterioration and no vertebral deformity 18 months after the operation.
Discussion Different varieties of development intradural cysts of the spinal cord include neurenteric cysts, enterogenous cysts, foregut cysts, teratomatous cysts, bronchiogenic cysts, arachnoid cysts, epethelial cysts, neuroepitheial cysts, colloid cysts, chorioependymal cysts, and ependymal cysts. Of these, the cysts lined with simple columnar or cuboid epithelium cause problems in the differential histological diagnosis from endodermal cysts. Generally, abscence of a basement membrane and lack of large scale glycoproteins are characteristic features of cysts of ependymal origin [3]. Immunocytochemical stains have aided in elucidating the
lines of differentiation of intracranial cysts. However, diagnosis by submicroscopical study provides the most confidence. Electron microscopy can characterize ependymal cysts as intracellular junction complexes, the absence of a basement membrane, membrane-bound granules in nonciliated cells, and absence of a coating on the luminal surface of the cells [5]. As for the pathogenesis of the cysts, the most widely accepted hypothesis is that the floor plate of the neural tube is evaginated on the ventral side and becomes isolated, then a cyst forms later [6]. This explanation may account for the presence of an ependymal cyst on the anterior side of the spinal cord. The location of isolated ependymal tissue determines whether the spinal cyst becomes extramedullary or intramedullary. Some authors suggest that pathogenesis of the extramedullary cyst may involve glioependymal ectopia [1,10]. Magnetic resonance imaging is the most useful radiographic method for evaluating spinal cysts. The borders of the cyst appear smooth and well
Spinal Intramedullary Ependymal Cyst
Coronal T1-weighted image after administration of gadolinium-DTPA does not show any enhancement of the cyst wall or spinal cord.
2
3
Surg Neurol 359 1999;52:357–61
defined, with a distinct and adjacent spinal cord. This is consistent with the surgical findings. Gadolinum-DTPA enhancement is necessary in the MR imaging of spinal cysts to distinguish tumor from a nonneoplastic cystic process; ependymal cyst walls are not enhanced. Some cases are diagnosed only by their magnetic resonance images without biopsy [11]. To our knowledge, there have been seven reported cases of spinal intramedullary ependymal cyst diagnosed pathologically (Table 1) [2,3,9,11, 13]. Six of these seven cysts were located at the thoracic level. In five reported cases, the walls of the cysts were not dissectable from the neural parenchyma even with the aid of an operating microscope, so biopsy was performed. In two cases, the cyst was enucleated because there was a plane of cleavage. Intramedullary ependymal cysts that have been biopsied or partially removed may recur in the future; therefore, it is necessary to carefully follow them [4,7,8]. Some extramedullary cysts have recurred after partial resection. Some cases of intramedullary cyst have been treated by marsupialization [12] or cyst-subarachnoid shunt [11]. It is best to totally enucleate the cyst without damage to the spinal cord. However, in some cases, including our case, this is very difficult because the cyst wall is adherent to the cord. Myelography was the diagnostic procedure previously used. Currently, however, MR imaging can provide a less invasive and more exact diagnosis. For spinal intramedullary ependymal cysts, we rec-
Photomicrograph of a biopsy specimen of the cyst wall (Hematoxylin and eosin stain ⫻100): Flattened cuboidal cell line on the glial stroma.
360 Surg Neurol 1999;52:357–61
Iwahashi et al
possible and create adequate communication between the cyst and the subarachnoid space.
REFERENCES
Magnetic resonance image at one month postoperatively: sagittal T1-weighted image shows reduced cyst in the anterior portion of the spinal cord at the T6 level.
4
ommend diagnostic MR imaging without myelography, followed by enucleation of the cyst, if possible. Otherwise, we remove the cyst wall as much as
1
NO.
1. Cooper IS, Kernohan JW. Heterotopic glial nests in subarachnoid space: histopathologic characteristic, mode of origin and relation to meningeal gliomas. J Neuropath Exp Neurol 1951;10:16 –29. 2. Dharker SR, Kankere S, Dharker RS. Intramedullary epithelial cyst of the spinal cord. Surg Neurol 1979; 12:443– 4. 3. Fortuna A, Palma L, Mercuri S. Spinal neuroepithelial cysts. Report of two cases and review of the literature. Acta Neurochirur 1978;45:177– 85. 4. Hashimoto T, Nakamura N, Yasue M, Fuse T, Funahashi K, Sekino H. Intraspinal neurenteric cyst associated with increased intracranial pressure. Neurol Med Chir (Tokyo) 1981;21:1183–9. 5. Hirano A, Ghatak NR, Wisoff HS, Zimmerman HM. An epithelial cyst of the spinal cord. An electron microscopic study. Acta Neuropath (Berl.) 1971;18:214 –23. 6. Hyman I, Hamby WB, Sanes S. Ependymal cyst of the cervicodorsal region of the spinal cord. Neurol Psychiat 1938;40:1005–12. 7. Morita Y, Kinoshita K, Wakisaka S, Makihara S. Fine surface structure of an intraspinal neuroenteric cyst. Neurosurgery 1990;27:829 –33. 8. Osenbach RK, Godersky JC, Traynelis VC, Schelper RD. Intracranial extramedullary cysts of the spinal canal. Neurosurgery 1992;30:35– 42. 9. Pagni CA, Canavero S, Vinattieri A, Forni M. Intramedullary spinal ependymal cyst: case report. Surg Neurol 1991;35:325– 8. 10. Popoff N, Feigin I. Heterotopic central nervous tissue in subarachnoid space. Arch Pathol 1964;78:533–7. 11. Robertson DP, Kirkpatrick JB, Harper RL, Mawad ME. Spinal intramedullary ependymal cyst. Report of three cases. J Neurosurg 1991;75:312– 6. 12. Rousseau M, Lesoin F, Combelles G, Krivoisic Y, Warot P. An intramedullary ependymal cyst in a 71year-old woman. Neurosurgery 1983;13:52– 4. 13. Sharma BS, Banerjee AK, Khosla VK, Kak VK. Congen-
Summary of Reported Cases of Intramedullary Spinal Ependymal Cyst With Pathological Study
AUTHOR
1. Fortuna (case 1) [3] 2. Fortuna (case 2) [3] 3. Dharker [2] 4. Roussearu [12] 5. Sharma [13] 6. Pagni [9] 7. Robertson (case 1) [11] 8. Iwahashi
YEAR AGE SEX
DURATION RADIOGRAPHIC OF METHOD FOR SYMPTOMS DIAGNOSIS LOCATION
SURGERY
RESULT
1978
67
F
5 Years
Myelography
T12
Biopsy
Partial recovery
1978
57
F
6 Years
Myelography
T12
Biopsy
Recovery
1979 1983 1987 1991 1991
38 71 7 39 48
F 1 Month F 53 Years M 1 Year M 2–4 Years F 3 Years
T6 T12 T4 C5-7 T12-L1
Biopsy Marsupialization Enucleation Enucleation Biopsy
No recovery Partial recovery Complete recovery Recovery Partial recovery
1997
1
Myelography Myelography Myelography MRI Myelography & MRI MRI
T6
Partial removal
Recovery
F
1 Month
Abbreviations: C ⫽ Cervical, T ⫽ Thoracic, L ⫽ Lumbar
Spinal Intramedullary Ependymal Cyst
Surg Neurol 361 1999;52:357–61
ital intramedullary spinal ependymal cyst. Surg Neurol 1987;27:476 – 80. COMMENTARY
This is a nice and well-documented report of an intramedullary ependymal cyst. These lesions are very rare and should not be misdiagnosed as a cystic tumor. MRI characteristics and histological features are well described by Iwahashi et al. One should remember that the cystic wall does not enhance after administration of gadolinium-DTPA.
Complete removal must be the goal of surgery; however, the walls are often difficult to dissect from the spinal cord parenchyma. Therefore, marsupialization of the cyst into the subarachnoid space should be done, but careful MRI follow-up is mandatory, because the lesion may recur if not totally removed. Jacques Brotchi, M.D., Ph.D. Service de Neurochirurgie Ho ˆpital Erasme Brussels, Belgium
f the defining perspective of the Cold War world was “division,” the defining perspective of globalization is “integration.” The symbol of the Cold War system was a wall, which divided everyone. The symbol of the globalization system is a World Wide Web, which unites everyone. The defining document of the Cold War system was “The Treaty.” The defining document of the globalization system is “The Deal.”
I
—Thomas L. Friedman “The Lexus and the Olive Tree” (1999)
Iwahashi H, Kawai S, Watabe Y, Chitoku S, Akita N, Fuji T, Oda T. Spinal intramedullary ependymal cyst: a case report. Surg Neurol 1999;52:357– 61. BACKGROUND
Spinal intramedullary ependymal cysts are extremely rare. Only seven pathologically proven cases have been reported in the literature. METHOD
We present an 18-month-old female with thoracic spinal intramedullary ependymal cyst that was diagnosed pathologically. RESULTS
Histological diagnosis was made by light microscopy after immunostaining. After partially removing the cyst wall and establishing communication between the cyst and the subarachnoid space, the patient improved neurologically. CONCLUSIONS
For spinal intramedullary ependymal cyst we recommend diagnosis by MR imaging without myelography, then enucleation of the cyst, if possible. Otherwise, we remove the cyst wall as much as possible and create adequate communication between the cyst and the subarachnoid space. © 1999 by Elsevier Science Inc. KEY WORDS
Intramedullary ependymal cyst, spinal cord.
pinal intramedullary ependymal cysts are extremely rare; only seven pathologically proven cases have been reported in the literature. We report here a patient with a spinal intramedullary ependymal cyst and discuss the pathological findings, pathogenesis, nature, and surgical management.
S
Address reprint requests to: Dr Hideaki Iwahashi, Department of Neurosurgery, Osaka Prefectural Hospital, 3-1-56 Bandaihigashi, Sumiyoshiku, Osaka, 558-8558 Japan. Received November 24, 1998; accepted January 25, 1999. © 1999 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
Case Report An 18-month-old female who could not stand up by herself was admitted to our hospital on April 9, 1997. She had been able to walk by herself at 10 months old, but motor weakness of the lower extremities developed at 1 year and 5 months old. Neurological examination on admission revealed a moderate paraparesis, with slightly exaggerated deep tendon jerks and extensor plantar (Babinski) response. Response to pain was dull. Spinal X-ray did not demonstrate any abnormal findings. MR imaging demonstrated a well defined intramedullary mass at the T6 level. The lesion was iso-intense to cerebrospinal fluid and demonstrated low intensity on T1-weighted images (Figure 1A) and high intensity on T2-weighted images (Figure 1B). After administration of Gd-DTPA there was no enhancement of the lesion on MR images (Figure 2). On April 16, 1997, T5-6 laminectomy was performed. Intradural exploration revealed a widened spinal cord without thickness or adhesion to the arachnoid membrane. The cord was swollen at the T6 level and a 7 mm midline myelotomy was performed at this portion. The cyst fluid was clear and colorless. The cyst wall was removed partially. Adequate communication was created between the cyst and the subarachnoid space. The cyst fluid protein concentration was 131 mg/dl. Histopathological study of the surgical specimens revealed that the cyst wall consisted of flattened cuboidal cells and and the underlying stroma was glial. There was no basement membrane seen (Figure 3). These lining cells lacked periodic acid-Schiff(PAS), alacian blue and muciacarmine positivity. Postoperative MR imaging showed a persistent but reduced cyst in the anterior portion of the spinal cord (Figure 4). After surgery, motor weakness and response to pain of the lower extremities grad0090-3019/99/$–see front matter PII S0090-3019(99)00097-X
358 Surg Neurol 1999;52:357–61
1
Iwahashi et al
Preoperative magnetic resonance images: Sagittal T1-weighted (A) and T2-weighted images (B) show an intramedullary cystic lesion at the T6 level.
ually improved. One month postoperatively the patient did not demonstrate any motor weakness and could walk by herself. The patient exhibited no neurological deterioration and no vertebral deformity 18 months after the operation.
Discussion Different varieties of development intradural cysts of the spinal cord include neurenteric cysts, enterogenous cysts, foregut cysts, teratomatous cysts, bronchiogenic cysts, arachnoid cysts, epethelial cysts, neuroepitheial cysts, colloid cysts, chorioependymal cysts, and ependymal cysts. Of these, the cysts lined with simple columnar or cuboid epithelium cause problems in the differential histological diagnosis from endodermal cysts. Generally, abscence of a basement membrane and lack of large scale glycoproteins are characteristic features of cysts of ependymal origin [3]. Immunocytochemical stains have aided in elucidating the
lines of differentiation of intracranial cysts. However, diagnosis by submicroscopical study provides the most confidence. Electron microscopy can characterize ependymal cysts as intracellular junction complexes, the absence of a basement membrane, membrane-bound granules in nonciliated cells, and absence of a coating on the luminal surface of the cells [5]. As for the pathogenesis of the cysts, the most widely accepted hypothesis is that the floor plate of the neural tube is evaginated on the ventral side and becomes isolated, then a cyst forms later [6]. This explanation may account for the presence of an ependymal cyst on the anterior side of the spinal cord. The location of isolated ependymal tissue determines whether the spinal cyst becomes extramedullary or intramedullary. Some authors suggest that pathogenesis of the extramedullary cyst may involve glioependymal ectopia [1,10]. Magnetic resonance imaging is the most useful radiographic method for evaluating spinal cysts. The borders of the cyst appear smooth and well
Spinal Intramedullary Ependymal Cyst
Coronal T1-weighted image after administration of gadolinium-DTPA does not show any enhancement of the cyst wall or spinal cord.
2
3
Surg Neurol 359 1999;52:357–61
defined, with a distinct and adjacent spinal cord. This is consistent with the surgical findings. Gadolinum-DTPA enhancement is necessary in the MR imaging of spinal cysts to distinguish tumor from a nonneoplastic cystic process; ependymal cyst walls are not enhanced. Some cases are diagnosed only by their magnetic resonance images without biopsy [11]. To our knowledge, there have been seven reported cases of spinal intramedullary ependymal cyst diagnosed pathologically (Table 1) [2,3,9,11, 13]. Six of these seven cysts were located at the thoracic level. In five reported cases, the walls of the cysts were not dissectable from the neural parenchyma even with the aid of an operating microscope, so biopsy was performed. In two cases, the cyst was enucleated because there was a plane of cleavage. Intramedullary ependymal cysts that have been biopsied or partially removed may recur in the future; therefore, it is necessary to carefully follow them [4,7,8]. Some extramedullary cysts have recurred after partial resection. Some cases of intramedullary cyst have been treated by marsupialization [12] or cyst-subarachnoid shunt [11]. It is best to totally enucleate the cyst without damage to the spinal cord. However, in some cases, including our case, this is very difficult because the cyst wall is adherent to the cord. Myelography was the diagnostic procedure previously used. Currently, however, MR imaging can provide a less invasive and more exact diagnosis. For spinal intramedullary ependymal cysts, we rec-
Photomicrograph of a biopsy specimen of the cyst wall (Hematoxylin and eosin stain ⫻100): Flattened cuboidal cell line on the glial stroma.
360 Surg Neurol 1999;52:357–61
Iwahashi et al
possible and create adequate communication between the cyst and the subarachnoid space.
REFERENCES
Magnetic resonance image at one month postoperatively: sagittal T1-weighted image shows reduced cyst in the anterior portion of the spinal cord at the T6 level.
4
ommend diagnostic MR imaging without myelography, followed by enucleation of the cyst, if possible. Otherwise, we remove the cyst wall as much as
1
NO.
1. Cooper IS, Kernohan JW. Heterotopic glial nests in subarachnoid space: histopathologic characteristic, mode of origin and relation to meningeal gliomas. J Neuropath Exp Neurol 1951;10:16 –29. 2. Dharker SR, Kankere S, Dharker RS. Intramedullary epithelial cyst of the spinal cord. Surg Neurol 1979; 12:443– 4. 3. Fortuna A, Palma L, Mercuri S. Spinal neuroepithelial cysts. Report of two cases and review of the literature. Acta Neurochirur 1978;45:177– 85. 4. Hashimoto T, Nakamura N, Yasue M, Fuse T, Funahashi K, Sekino H. Intraspinal neurenteric cyst associated with increased intracranial pressure. Neurol Med Chir (Tokyo) 1981;21:1183–9. 5. Hirano A, Ghatak NR, Wisoff HS, Zimmerman HM. An epithelial cyst of the spinal cord. An electron microscopic study. Acta Neuropath (Berl.) 1971;18:214 –23. 6. Hyman I, Hamby WB, Sanes S. Ependymal cyst of the cervicodorsal region of the spinal cord. Neurol Psychiat 1938;40:1005–12. 7. Morita Y, Kinoshita K, Wakisaka S, Makihara S. Fine surface structure of an intraspinal neuroenteric cyst. Neurosurgery 1990;27:829 –33. 8. Osenbach RK, Godersky JC, Traynelis VC, Schelper RD. Intracranial extramedullary cysts of the spinal canal. Neurosurgery 1992;30:35– 42. 9. Pagni CA, Canavero S, Vinattieri A, Forni M. Intramedullary spinal ependymal cyst: case report. Surg Neurol 1991;35:325– 8. 10. Popoff N, Feigin I. Heterotopic central nervous tissue in subarachnoid space. Arch Pathol 1964;78:533–7. 11. Robertson DP, Kirkpatrick JB, Harper RL, Mawad ME. Spinal intramedullary ependymal cyst. Report of three cases. J Neurosurg 1991;75:312– 6. 12. Rousseau M, Lesoin F, Combelles G, Krivoisic Y, Warot P. An intramedullary ependymal cyst in a 71year-old woman. Neurosurgery 1983;13:52– 4. 13. Sharma BS, Banerjee AK, Khosla VK, Kak VK. Congen-
Summary of Reported Cases of Intramedullary Spinal Ependymal Cyst With Pathological Study
AUTHOR
1. Fortuna (case 1) [3] 2. Fortuna (case 2) [3] 3. Dharker [2] 4. Roussearu [12] 5. Sharma [13] 6. Pagni [9] 7. Robertson (case 1) [11] 8. Iwahashi
YEAR AGE SEX
DURATION RADIOGRAPHIC OF METHOD FOR SYMPTOMS DIAGNOSIS LOCATION
SURGERY
RESULT
1978
67
F
5 Years
Myelography
T12
Biopsy
Partial recovery
1978
57
F
6 Years
Myelography
T12
Biopsy
Recovery
1979 1983 1987 1991 1991
38 71 7 39 48
F 1 Month F 53 Years M 1 Year M 2–4 Years F 3 Years
T6 T12 T4 C5-7 T12-L1
Biopsy Marsupialization Enucleation Enucleation Biopsy
No recovery Partial recovery Complete recovery Recovery Partial recovery
1997
1
Myelography Myelography Myelography MRI Myelography & MRI MRI
T6
Partial removal
Recovery
F
1 Month
Abbreviations: C ⫽ Cervical, T ⫽ Thoracic, L ⫽ Lumbar
Spinal Intramedullary Ependymal Cyst
Surg Neurol 361 1999;52:357–61
ital intramedullary spinal ependymal cyst. Surg Neurol 1987;27:476 – 80. COMMENTARY
This is a nice and well-documented report of an intramedullary ependymal cyst. These lesions are very rare and should not be misdiagnosed as a cystic tumor. MRI characteristics and histological features are well described by Iwahashi et al. One should remember that the cystic wall does not enhance after administration of gadolinium-DTPA.
Complete removal must be the goal of surgery; however, the walls are often difficult to dissect from the spinal cord parenchyma. Therefore, marsupialization of the cyst into the subarachnoid space should be done, but careful MRI follow-up is mandatory, because the lesion may recur if not totally removed. Jacques Brotchi, M.D., Ph.D. Service de Neurochirurgie Ho ˆpital Erasme Brussels, Belgium
f the defining perspective of the Cold War world was “division,” the defining perspective of globalization is “integration.” The symbol of the Cold War system was a wall, which divided everyone. The symbol of the globalization system is a World Wide Web, which unites everyone. The defining document of the Cold War system was “The Treaty.” The defining document of the globalization system is “The Deal.”
I
—Thomas L. Friedman “The Lexus and the Olive Tree” (1999)