Surgical Science, 2011, 2, 297-302
doi:10.4236/ss.2011.26064 Published Online August 2011 (http://www.SciRP.org/journal/ss)
Copyright © 2011 SciRes. SS
Delayed Manifestation of Sacral Clear Cell
Meningioma Distent Metastasis or
Multifocal Disease?
Habib Nouri1, Leila Abid2, Moez Ouertatani1, Dalenda Hentati3, Mondher Mestiri2, Habib Jaafoura2
1Department of Adult Surgery, Kassabs Institute, Tunisia
2Department of Pathology”, Kassabs Institute, Tunisia
3Department of Radiat i o n Therapy, National Institute of Oncology, Tunisia
E-mail: nourihabib@yahoo.fr
Received December 6, 2010; revised December 26, 2010; accepted January 13, 2011
Abstract
Study Design: the authors report on a clear cell meningioma (CCM) of the sacrum revealed 17 years after a
removal of a spinal lesion. A review of 29 spinal CCM previously reported was done. Objective: To focus on
clinical and biological behaviour of CCM. Summary of Background Data: CCM is a rare subtype charac-
terrized by its inordinately aggressive clinical course despite its benign appearance. The tumour shows pro-
clivity for the cerebellopontine angle and cauda equine region. Recurrence and metastasis have been com-
monly reported. Method: a 26 year-old man presented with low back pain related to a lytic lesion of the sa-
crum. He had a history of an intradural extramedullary meningioma of the cervical spine removed when he
was 9 year-old. CT scan revealed a sacral osteolytic lesion with anterior and lateral extension. Open biopsy
revealed a clear cell meningioma. That was the same pattern of the tumour removed 17 years before. Results:
Our patient was managed conservatively by palliative radiation therapy. At 2 years follow-up, he experi-
enced improvement of pain and walking. Conclusion: CCM is an aggressive tumour with a high risk of me-
tastases through cerebrospinal fluid. A follow up with spinal MRI should be performed.
Keywords: Clear Cell Meningioma, Spine, Cerebrospinal Fluid, Metastasis, Local Recurrence, Radiation
Therapy, Pathology
1. Introduction
Meningiomas are the most common primary tumours of
the central nervous system. Approximately 90% to 95%
of them are classified as grade I according to the World
Health Organization (WHO) 2007 criteria [1], whereas 5
to 7% are graded II and 1 to 2.8% are graded III. Clear
cell meningiomas (CCM) are rare and have been re-
ported in only 0.2% of cases [2]. They are graded II or
aggressive. The tumour shows proclivity for the cere-
bellopontine angle and cauda equine region. Despite its
benign appearance, CCM has an aggressive behaviour
and recurrence and metastasis has been commonly re-
ported.
Here we report an unusual case of a metastatic clear
cell meningioma to the sacrum, discovered 17 years after
total resection of the primary cervical lesion. The clinical
and pathological features are discussed.
2. Case Report
A 26 year-old male was referred to our department in
2007 for a tumour of the sacrum. He underwent in 1990
when he was 9 year-old a resection of an intraspinal tu-
mour. Cervical CT scan had revealed an intraduralex-
tramedullary tumor measuring 2 cm at the level of C4-C5.
The tumor was well-circumscribed, homogeneous, lo-
cated posteriorly, and compressing the spinal cord. The
tumor was excised totally. Pathological examination had
revealed a particular meningioma characterized by the
presence of mycrocystic cells and prominent interstitial
collagen which separate or enclose the cellular aggre-
gates. A Masson’s trichrome stain highlighted the abun-
dant collagen component. The neoplastic cells were ar-
ranged in sheets and forming a rare whorls. The stromal
blood vessels have a thick hyalinized wall. The patient
got no further therapy and follow-up was uneventful for
H. NOURI ET AL.
298
17 years.
His complaints were progressive sacral pain and con-
stipation. There was neither mass nor neurological deficit
in clinical findings.
Plain radiographs showed a radiolucent expansion of
the sacrum (Figure 1). Pelvic CT scan revealed a huge
mass involving the entire sacrum, expanding anteriorly
and invading the ilio-sacral joints (Figures 2(a) and (b)).
Cervical spinal CT scan didn’t show any local recurrence
of the primary lesion.
An open biopsy in the sacrum was performed. His-
tologically, the tumour was composed of sheets of po-
lygonal cells with clear cytoplasm and prominent inter-
stitial collagen (Figure 3(a)). Neoplastic cells had ve-
sicular, round to oval nuclei and small nucleoli. There
was no significant cytological atypia or pleomorphism.
No mitotic figures were identified (Figure 3(b)). The
cells have an abundant clear cytoplasm PAS-positive due
to glycogen accumulation. In particular, there were nu-
merous concentrically laminated eosinophilic, colla-
genous structures intersecting throughout the lesion.
However, typical psammoma bodies were not seen. Only,
a few vague whorls were seen. Extensive immunohisto-
chemistry has been performed. The neoplastic cells
stained strongly diffuse positivity for vimentin. The tu-
mor cells were also positive for EMA and S100. Moder-
ate positivity was demonstrated with progesterone re-
ceptor (Figure 3(c)). The cells showed negative staining
with cytokeratin, chromogranine and glial fibrillary pro-
tein. The reactivity of the tumor cells with the antibody
MIB-1 showed a very low labelling index and the per-
centage of cells that expressed MIB-1 was about 1%.
On the basis of these histological findings, the diagno-
sis was that of clear cell meningioma. Primary histologi-
cal specimens taken at the age of 9 years were available
for study and showed the same features of the sacral tu-
Figure 1. P lain radiographe AP view showing a radiolucent
expension of the sacrum.
(a)
(b)
Figure 2. CT scan of the pelvis. (a) axial view showing an
osteolytic lesion of the sacrum invading the intrapelvic or-
gans anteriorly and the ilio-sacral joints laterally; (b) sagit-
tal reconstruction. The tumor mass invaded the spinal canal
and the presacral space. Note that posterior extension is
limited.
mour. Therefore we concluded to an osseous metastatic
clear cell meningioama. Chest CT scan was negative. The
patient received palliative radiation therapy consisting of
6000 cGy delivered in 30 fractions. Four years later, he
was still alive, he experienced improvement of pain. The
mass was stable on control CT scan (Figure 4).
3. Discussion
Our case with primary extracranial CCM and the so far
metastasis to the sacrum is unique. It presented mainly 2
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H. NOURI ET AL.299
(a)
(b)
(c)
Figure 3. (a) Microscopically, the tumour is composed of
patternless sheets of clear-cells in a collagen background
(Hematoxylin and eosin, original magnification × 200); (b)
neoplastic cells had vesicular, round to oval nuclei and
small nucleoli. The cells have an abundant clear cytoplasm
PAS-positive; (c) tumour cells show a moderate immuno-
reactivity for progesterone receptor.
Figure 4. CT scan 4 years later. The mass is stable.
problems, a therapeutic one characterised by the absence
of a consensus in literature. Secondly, the relationship
between the present tumor and the primary cervical le-
sion remains unclear.
Clear cell meningioma is perhaps the rarest of the tu-
mors of meningothelial origin. Among 485 cases, K-W
ko et al. [3] found 3 CCMs (0.6%). Zorludemir et al. [2]
reported the largest series of 13 cases of CCM. The most
frequent site of involvement was the spinal intradural
region (56%). Twenty nine documented cases of spinal
CCMs reported previously were found from literature
[2,4-24]. Clinical data and outcome are summarised in
the Table 1. CCM seems to affect young patient with a
mean age of 22.4 years +/18.2 (median: 19 years), al-
though both paediatric and elderly patients are involved
(1.2 - 72 years). It appears to be a female predominance
(F/M: 1.72). The most frequent location observed was
the cauda equine. Cervical spine was involved in 5 cases
only (16.7%).
The importance of recognising this particular variant
of meningioma relates specifically to its inordinately
aggressive clinical course despite its benign appearance.
Unlike the more typical meningioma, CCM’s propensity
for local recurrence has been well-established in the lit-
erature. The rate of recurrence found in this study was
40% (vs 4.8% for non CCMs) [25,26]. Although rare
event (7%), spinal metastasis in meningiomas is well
established [25,27-33]. It occurs either through ha-
ematogenous route or cerebro-spinal fluid. Metastases
occur in aproximately 0.2% of intracranial tumours [33].
Only 7% of them occur in vertebrae [33,34] and not all
meningiomas that metastasize are malignant. More than
60% of them originated from grade I meningiomas
[26,29]. Nevertheless, distant metastases are known to be
relatively more frequent arising from grade II or III sub-
types [35,36]. Malignant meningiomas seem to spread
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H. NOURI ET AL.
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300
through CSF more frequently [29,37-39]. However the
risk of CSF dissemination is not clear from literature. It
remains controversial whether surgical procedures may
play a role in the spread of the tumour via CSF [37,38].
Most of patients were operated on several times before a
metastasis occurred. Although, some cases seem to occur
in non-operated patients [26,40]. The lumbo-sacral re-
gion was a common site for spinal metastases [27]. The
first case of a metastatic meningioma to the sacrum was
reported by Lee [29] in 2002. However, whether distant
recurrences represent the capacity of CCM to metastasize
or a multifocal characteristic remains uncertain. Multi-
focal manifestation of CCM is well-described and the
distant recurrences may represent this [41]. To our know-
ledge, only one documented case of synchronous multi-
centric CCM was reported [9]. Our case seems to be
more likely a distant recurrence because of a drop me-
tastasis rather than a multifocal presentation but we
couldn’t conclude since the entire neuraxis was not im-
aged initially. This emphasizes the necessity to explore
the entire spine by MRI in cases of spinal meningioma.
The latency period between the diagnosis of primary
tumour and the appearance of metastasis reported in lit-
erature is variable, ranging from few months to more tan
20 years [41]. In our case, the latency of 17 years can be
explained by two facts: firstly, the very low mitotic ac-
tivity attests that it’s a slow growing lesion. Secondly,
the location to the sacrum and the anterior extension of
Table 1. Summary of intraspinal CCMs observed in present and previous reports. GTR: gross total resection; STR: subtotal
resection; RT: radiation therapy.
Author/year Age/sex Tumor location Treatment Outcome (recurrence metastasis)
Zorludemir (2) 1995
9/F 17/F
23/F 34/M
36/F 47/M
L3-L5 L4-L5
L5 L4-S1
L2-L5 L3-L4
GTR GTR
GTR GTR
GTR GTR + RT
Recurrence at 6 months No No
Recurrence at 2 months No
Recurrence at 36 months, and brain metastasis
Prinz (4) 1996 38/M Sacrococcygeal GTR Multiple recurrences
Holtzman (5) 1996 32/M L3-L4 GTR No
Pimentel (6) 1998 55/M 21/F Cervical Lumbar GTR GTR No No
Cances (7) 1998 9/F L1-L4 GTR + RT Recurrence at 5 months
Dubois (8) 1998 10/F Cauda equine GRT+RT Recurrence at 6 months
Matsui (9)1998 9/F Multifocal T12, L2, L5GTR No
Jallo (10) 2001 1,8/F 8/F C3-C5 L3-L5 STR GTR Recurrence at 10 weeks and brain metastasis
Recurrence at 6 months
Yu (11) 2002 1.2/F T12-L1 GTR Recurrence at 4 months
Boet (12) 2004 34/M Lumbosacral STR + RT No
Liu (13) 2005 2.2/F T10-L1 GTR Recurrence at 60 months
Dhall (14) 2005 32/F Thoraco lumbar STR Recurrence
Jain (15) 2007 26/F Cauda equine GTR No
Colen (16) 2009 13/F L4-L5 GTR + RT No
Tong-tong (17) 2010 35/F C7 GTR No
Inoue (18) 2004 72/M C5-C6 GTR No
Heth (19) 2000 7/F L4-L5 GTR No
Oviedo (20) 2005 7/M L2-L3 GTR No
Epstein (21) 2005 41/F L3-L4 GTR No
Park (22) 2000 1.2/F Cauda equine GTR Recurrence at 18 months
Carra (23) 2001 1.9/M T11-L4 GTR No
Chen (24) 2004 41/F L4-L5 GTR No
Present report 9/M C4 GTR Sacral metastasis at 17 years
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the tumour explain how such a huge mass could remain
asymptomatic for a long period.
Prognosis of spinal metastases is related to their clini-
cal progression. When it was rapid, death usually oc-
curred soon after the time of initial diagnosis. The prog-
nosis is especially bad in patients with neurologic deficit.
Treatment of spine metastatic meningiomas is pallia-
tive. Patients that had undergone surgical debulking
[27,28,31,35,36,42] showed no neurological improve-
ment. Palliative radiation therapy is the preferred modal-
ity of treatment. Although, irradiation has shown some
symptomatic relief, the paucity of cases doesn’t allow
clear conclusions concerning its real effect on survival
rate. Lee et al [38] used steroid for their 3 patients com-
bined to irradiation and reported some symptomatic im-
provement. Adjunction of steroid seems to be interesting
since neoplastic cells demonstrate positivity for proges-
terone receptors.
4. Conclusions
Clear cell meningioma constitutes a rare subset of ma-
lignant meningiomas. It has an aggressive clinical course
despite its histological appearance. A close follow-up
would be required due to the high risk of recurrence and
metastases. The early detection and irradiation of metas-
tatic lesions can improve their prognosis.
5. References
[1] D. Louis, Ohgaki, H. Wiestler, et al., “WHO Classifica-
tion—Tumours of the Nervous System,” 4th Edition, In-
ternational Agency for Research on Cancer, Lyon, 2007,
pp. 164-172.
[2] S. Zorludemir, B. W. Scheithauer, T. Hirose, et al., “Cler
Cell Meningioma: A Clinicopathologic Study of a Poten-
tially Aggressive Variant of Meningioma,” The American
Journal of Surgical Pathology, Vol. 19, No. 5, 1995, pp.
493-505. doi:10.1097/00000478-199505000-00001
[3] K. W. Ko, D. H. Nam, D. S. Kong, et al., “Relationship
between Malignant Subtypes of Meningioma and Clinical
Outcome,” Journal of Clinical Neuroscience, Vol. 14, No.
8, 2007, pp. 747-753. doi:10.1016/j.jocn.2006.05.005
[4] M. Prinz, S. Patt, T. Mitrovics, et al., “Clear Cell Men-
ingioma: Report of a Spinal Case,” General & Diagnostic
Pathology, Vol. 141, No. 3-4, 1996, pp. 261-267.
[5] R. N. N. Holtzman and S. C. Jorkman, “Nondural-Based
Lumbar Clear Cell Meningioma,” Journal of Neurosur-
gery, Vol. 84, No. 2, 1996, pp. 264-266.
doi:10.3171/jns.1996.84.2.0264
[6] J. Pimental, A. Fernandes, A. E. Pinto, et al., “Clear Cell
Meningioma Variant and Clinical Aggressiveness,” Clin-
ical Neuropathology, Vol. 17, No. 3, 1998, pp. 141-146.
[7] C. Cances, Y. Chaix, C. Karsenty, et al., “Clear Cell Me-
ningioma: Recurrent Intraspinal Tumor in a Child,” Ar-
chives de Pédiatrie, Vol. 5, No. 7, 1998, pp. 758-762.
doi:10.1016/S0929-693X(98)80062-6
[8] A. Dubois, A. Sevely, S. Boetto, et al., “Clear Cell Men-
ingioma of the Cauda Equine,” Neuroradiology, Vol. 40,
No. 11, 1998, pp. 743-747.
doi:10.1007/s002340050676
[9] H. Matsui, M. Kanamori, Y. Abe, et al., “Multifocal Clear
Cell Meningioma in the Spine: A Case Report,” Neurosur-
gical Review, Vol. 21, No. 2-3, 1998, pp. 171-173.
doi:10.1007/BF02389326
[10] G. I. Jallo, K. F. Kothbauer, V. M. Silvera, et al., “In-
traspinal Clear Cell Meningioma: Diagnosis and Man-
agement: Report of Two Cases,” Neurosurgery; Vol. 48,
No. 1, 2001, pp. 218-222.
[11] K. B. Yu, M. K. Lim, H. J. Kim, et al., “Clear Cell Men-
ingioma: CT and MR Imaging Findings in Two Cases
Involving the Spinal Canal and Cerebellopontine Angle,”
Korean Journal of Radiology, Vol. 3, No. 2, 2002, pp.
125-129. doi:10.3348/kjr.2002.3.2.125
[12] R. Boet, H. K. Ng, S. Kumta, et al., “Lumbosacral
Clear-Cell Meningioma Treated with Subtotal Resection
and Radiotherapy,” Journal of Clinical Neuroscience,
Vol. 11, No. 4, 2004, pp. 432-436.
doi:10.1016/j.jocn.2003.10.014
[13] P. I. Liu, G. C. Liu, K. B. Tsai, et al., “Intraspinal Clear
Cell Meningioma: Case Report and Review of Litera-
ture,” Surgical Neurology, Vol. 63, No. 3, 2005, pp.
285-289. doi:10.1016/j.surneu.2004.03.013
[14] S. S. Dhall, L. M. Tumialan, D. J. Brat, et al., “Spinal
Intradural Clear Cell Meningioma Following Resection
of a Suprasellar Clear Cell Meningioma. Case Report and
Recommendations for Management,” Journal of Neuro-
surgery, Vol. 103, No. 3, 2005, pp. 559-563.
doi:10.3171/jns.2005.103.3.0559
[15] D. Jain, M. C. Sharma, C. Sarkar, et al., “Clear Cell Me-
ningioma, an Uncommon Variant of Meningioma: A Cli-
nicopathologic Study of Nine Cases,” Journal of Neu-
ro-Oncology, Vol. 81, No. 3, 2007, pp. 315-321.
doi:10.1007/s11060-006-9237-7
[16] C. B. Colen, M, Rayes, J. McClendon Jr., et al., “Pediat-
ric Spinal Clear Cell Meningioma. Case Report,” Journal
of Neurosurgery Pediatrics, Vol. 3, No. 1, 2009, pp.
57-60.
[17] T.-T. Wu, L.-J. Bian, Z. Li, Y. Li, B.-N. Luo and Q.
Huang, “Clear Cell Meningioma with Anaplastic Features:
Case Report and Review of Literature,” Pathol-
ogy—Research and Practice, Vol. 206, No. 5, 2010, pp.
349-354. doi:10.1016/j.prp.2009.06.015
[18] T. Inoue, K. Miyamoto, H. Kodama, et al., “Cervical
Clear Cell Meningioma Mimicking a Vertebral Metasta-
sis,” Journal of Clinical Neuroscience, Vol. 12, No. 6,
2005, pp. 685-687. doi:10.1016/j.jocn.2004.08.019
[19] J. A. Heth, P. Kirby, A. H. Menezes, et al., “Intraspinal
Familial Clear Cell Meningioma in a Mother and Child,”
Journal of Neurosurgery, Vol. 93, No. 2, 2000, pp.
317-321.
[20] A. Oviedo, D. Pang, J. Zovikian, et al., “Clear Cell Men-
ingioma: Case Report and Review of the Literature,” Pe-
H. NOURI ET AL.
302
diatric and Developmental Pathology, Vol. 8, No. 3,
2005, pp. 386-390. doi:10.1007/s10024-005-0119-3
[21] N. Epstein, S. Drexler and J. Shneider, “Clear cell Men-
ingioma of the Cauda Equine in an Adult. Case Report and
Literature Review,” Journal of Spinal Disorders & Tech-
niques, Vol. 18, No. 6, 2005, pp. 539-543.
doi:10.1097/01.bsd.0000173314.98401.b5
[22] H. C. Park, M. J. Sohn, E. Y. Kim, et al., “Spinal Clear
Cell Meningiomas Presented with Progressive Parapresis
in Infancy,” Childs Nervous System, Vol. 16, No. 9,
2000, pp. 607-610. doi:10.1007/PL00007302
[23] S. Carra, P. Drigo, M. Gadriman, et al., “Clear Cell Me-
ningioma in a 22 Months-Old Male; a Case Report and
Literature Review,” Pediatric Neurosurgery, Vol. 34, No.
5, 2001, pp. 264-267.
[24] M. H. Chen, S. J. Chen, S. M. Lin, et al., “A Lumbar
Cleare Cell Meningioma with Foraminal Extension in a
Renal Transplant Recipient,” Journal of Clinical Neuro-
science, Vol. 11, No. 6, 2004, pp. 665-667.
doi:10.1016/j.jocn.2003.10.024
[25] S. K. Ludwin and F. K. Conley, “Malignant Meningioma
Metastatizing through the Cerebrospinal Pathways,”
Journal of Neurology, Neurosurgery & Psychiatry, Vol.
38, No. 2, 1975, pp. 136-142. doi:10.1136/jnnp.38.2.136
[26] P. M. Son, M. Sacher, S. W. Strenger, et al., “Benign
Metastasizing Meningiomas,” American Journal of Neu-
roradiology, Vol. 8, No. 1, 1987, pp. 127-130.
[27] A. T. kimura, T. Orita, O. Hayashida, et al., “Malignant
Meningiomas Metastatizing through the Cerebrospinal
Pathway,” Acta Neurologica Scandinavica, Vol. 85, No.
5, 1992, pp. 368-371.
doi:10.1111/j.1600-0404.1992.tb04063.x
[28] K. Kamiya, T. Inagawa and R. Nagasako, “Malignant
Intraventricular Meningioma with Spinal Metastasis
through the Cerebrospinal Fluid,” Surgical Neurology,
Vol. 32, No. 3, 1989, pp. 213-218.
doi:10.1016/0090-3019(89)90181-X
[29] Y. Y. Lee, W. W. Hsu, T. J. Huang, et al., “Metastatic
Meningioma in the Sacrum: A Case Report,” Spine, Vol.
27, No. 4, 2002, pp. E100-E103.
doi:10.1097/00007632-200202150-00022
[30] W. C. Peh and Y. W. Fan, “Case Report: Intraventricular
Meningioma with Cerebelopontine Angle and Drop Me-
tastases,” The British Journal of Radiology, Vol. 68, No.
808, 1995, pp. 428-430.
doi:10.1259/0007-1285-68-808-428
[31] C. G. Riley, “Metastatizing Meningeal Tumour Case
Report,” The New Zealand Medical Journal, Vol. 73,
1974, pp. 210-214.
[32] F. J. Wippold II, J. G. Smimoitopoulos and T. K. Pilgram,
“Lesions of the Cauda Equine: A Clinical Pathology Re-
view from the Armed Forces Institute of Pathology,”
Clinical Neurology and Neurosurgery, Vol. 9, No. 4,
1997, pp. 229-234. doi:10.1016/S0303-8467(97)00095-4
[33] J. L Karasik and S. Mullens, “A Survey of Metastatic
Meningiomas,” Journal of Neurosurgery, Vol. 40, No. 2,
1974, pp. 206-212. doi:10.3171/jns.1974.40.2.0206
[34] R. Wasserkurg, E. Peyser and C. Lichtig, “Extracranial
Bone Metastases from Intracranial Meningiomas,” Surgical
Neurology, Vol. 12, No. 6, 1979, pp. 480-484.
[35] M. D. Conrad, C. Schonauer, I. Pelissou-Guyotat, et al.,
“Recurrent Lumbosacral Metastases from Intracranial
Meningioma. Report of a Case and Review of the Litera-
ture,” Acta Neurochirurgica, Vol. 143, No. 9, 2001, pp.
935-937. doi:10.1007/s007010170024
[36] S. A. Enam, S. Abdulrauf, B. Mehta, et al., “Metastasis in
Meningioma,” Acta Neurochirurgica, Vol. 138, No. 10,
1996, pp. 1172-1178. doi:10.1007/BF01809747
[37] M. C. Chamberlain and M. J. Glantz, “Cerebrospinal Fluid-
Dessiminated Meningioma,” Cancer, Vol. 103, No. 7,
2005, pp. 1427-1430. doi:10.1002/cncr.20926
[38] T. T. Lee and H. J. Landy, “Spinal Metastases of Malig-
nant Intracranial Meningioma,” Surgical Neurology, Vol.
50, No. 5, 1998, pp. 437-441.
doi:10.1016/S0090-3019(97)00348-0
[39] P. D. Delgado-Lopez, V. Martin-Velasco, J. M. Castilla-
Diez, et al., “Metastatic Meningioma to the Eleventh
Dorsal Vertebal Body: Total En Bloc Spondylectomy.
Case Report and Review of the Literature,” Neur- ocirur-
gia, Vol. 17, No. 3, 2006, pp. 240-249.
[40] S. W. Strenger, Y. P. Huang and V. P. Sachdez, “Malig-
nant Meningioma within the Third Ventricle: A Case
Report,” Neurosurgery, Vol. 20, No. 3, 1978, pp.
465-468. doi:10.1227/00006123-198703000-00019
[41] W. Lee, K. H. Chang, G. Choe, et al., “MR Imaging Fea-
tures of Clear Cell Meningioma with Diffuse Lep- to-
meningeal Seeding,” American Journal of Neuror-
adiology, Vol. 21, No. 1, 2000, pp. 130-132.
[42] S. Fuentes, P. Metellus, C. Bouvier, et al., “Metastatic
Meningioma to the First Thoracic Vertebral Body. A
Case Report and Review of the Literature,” Neurochirur-
gie, Vol. 48, No. 1, 2002, pp. 53-56.
Copyright © 2011 SciRes. SS