Kistik menenjiyomlar: üç olgu sunumu

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Introduction
Cystic meningiomas are uncommon and their incidence has been reported to be 1.6 to 10% in all types
of meningiomas (1-6). Cysts are frequently associated
with glial or metastatic tumors. Thus, it may be difficult to differentiate them from metastatic neoplasms,
hemangioblastomas, neuroblastomas, and glial tumors with cystic components, and histopathological examination will define the diagnosis (6-13). We
herein report three cases of cystic meningiomas and
discuss the characteristics of these lesions comparing
to the articles reached by Pubmed research.
Case Reports
Case 1
A 72-year-old woman was admitted to our clinic for
focal seizures. In her neurological examination there
were left-sided lower extremity paresis and positive
Babinski’s sign. Computed tomography (CT) scans
showed a large low-density mass in the right posterior frontal region surrounded by a hypodense zone
of edema. Gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) demonstrated a cystic
tumor in the parasagittal area and right pontocerebellar meningioma (Figure 1A,B). A craniotomy was
performed. Peritumoural cyst was containing xanthochromic fluid, which surrounded the tumor mass,
and a soft tumor adjacent to the parasagittal region
but not attached to the dura was found. The tumor
and cystic wall were completely removed (Figure 1C).
Histopathological studies revealed the diagnosis of a
meningothelial meningioma. The postoperative course was uneventful and the patient was discharged
on the 10th postoperative day. There was no residual
tumor or cyst in follow-up period.
Case 2
A 62-year-old woman was admitted with a headache and vertigo. In her neurological examination
* Department of Neurosurgery, Gulhane Military Medical Academy
Haydarpaşa Training Hospital, İstanbul, Turkey
**Department of Pathology, Gulhane Military Medical Academy Haydarpaşa
Training Hospital, İstanbul, Turkey
Reprint request: Dr. Selçuk Göçmen, Department of Neurosurgery, Gulhane
Military Medical Academy Haydarpaşa Training Hospital, İstanbul, Turkey
E-mail: s_gocmen@yahoo.com
Date submitted: December 15, 2010 • Date accepted: March 03, 201170 • March 2011 • Gulhane Med J Göçmen et al.
Figure 1. Gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) of the first case demonstrated a cystic tumor in the
parasagittal area (A) and right pontocerebellar meningioma (B). The tumor was seen after completely removed (C)
Discussion
Meningiomas are generally solid tumors and the
presence of such cystic areas is relatively rare. In fact,
so-called cystic meningiomas account for only 2-10%
of intracranial meningiomas (1,10,14,15). In 1932,
Penfield first described cystic changes in meningioma (16). Fortuna et al. presented the largest series, in
which 22 cystic meningiomas out of 1,313 intracranial
meningiomas (1.7%) were operated on in a 35-year period (1). Cystic meningiomas are more common in the
pediatric age group than in adolescence or adulthood
(17). The incidence of cyst formation of meningiomas
is especially high in infancy (17). Reports of cystic meningiomas have been more frequent since the advent
of CT and MRI scans (18). The use of CT and MRI has
greatly improved our ability to locate and identify the
tumor with dural attachment, with a histological predictive accuracy approaching 90% (18).
Igaki et al. reported the uncommon late radiation
morbidity of cyst formation after stereotactic radiosurgery for meningioma. The rate of this morbidity
has been estimated to be 0.7-1.7% in these previous
reports. In our cases, none of the cystic meningiomas
had previous radiotherapy (19).
Different types of cystic meningiomas have been
described. Rengachary et al. recognized two types of
cysts within or around the meningioma: intratumoral and extratumoral (20). Subsequently, Nauta et al.
classified cystic meningiomas into four types based
on location of the cavity and the relationship between the tumor and the surrounding brain: 1) centrally located intratumoral cyst; 2) peripherally located intratumoral cyst, 3) peritumoral cyst in the adjacent parenchyma, and 4) peritumoral cyst between
the tumor and the adjacent parenchyma (21). Finally,
a fifth type with entrapped cerebrospinal fluid (CSF)
there was left temporal hemianopsia. CT and MRI
studies demonstrated a cystic tumor in the right falx
region and left lateral ventricular lesion (Figure 2C).
The right occipital lobe was explored with neuronavigation system, and a peritumoral cyst containing
xanthochromic fluid, which surrounded the tumor
mass was observed. The tumor and the entire cyst
wall were completely removed. Histopathological
studies revealed the diagnosis of an angiomatous
meningioma (Figure 2A,B). After an uneventful postoperative course, the patient was discharged on the
6th post-operative day.
Case 3
The 53-year-old woman presented with a history
of headache and dizziness beginning one month before her admission to the hospital. She had previously had a central facial palsy on the right side. The
neurologic examination revealed a cerebellar ataxia
and sequela of facial palsy. A CT scan demonstrated
a cystic tumor in the posterior fossa. MRI showed a
homogeneously enhancing solid mass attached to
the undersurface of the tentorium with a large cyst
with a non-enhancing wall in the cerebellum (Figure
3A,B). This finding strongly suggested a meningioma, but we also considered a malignant tumor. It
was attached to the dura and bone, wholly extraaxial,
and separated from the surrounding normal cerebellum tissue by a cystic wall. The cyst contained yellowish fluid. The tumor was completely removed with
its dural attachment via a suboccipital craniotomy.
Histopathological studies showed a meningothelial
meningioma. Postoperatively, she made an uneventful recovery. There was no residual tumor or cyst in
follow-up contrast enhanced CT scan. The clinical
findings are summarized in Table I.Volume 53 • Issue 1 Cystic meningiomas • 71
was added by Worthington et al. (15). Weber et al.
subdivided the peritumoral types: the cyst wall containing tumor cells and without tumor invasion (13).
Zee et al. divided cystic meningiomas into three subgroups: intratumoral cysts, peritumoral cysts with the
wall enhancing on MRI, and peritumoral cysts with
wall not enhancing (6).
Classification of Nauta et al. seem more practical
(21). In our series, we detected type 1 cysts in our first
and third cases; while a type 2 cyst was detected in
the second case according to the Nauta classification.
Pathophysiological mechanisms in the formation
of meningioma cysts are discussed by various authors
(2,15,16,20,22-24). Penfield et al. have suggested that
Table I. Summary of the characteristics of cystic meningiomas
Case No. Age (years)/sex Main complaint Location Subtype Cyst type (21) Surgery/Fluid Second lesion
1 72/F Seizure Right-parietal/
parasagittal
Meningothelial 1 Total removal/
xanthochromic
Ponto-cerebellar
meningioma
2 62/F Headache, vertigo Right occipital/
Falx
Angiomatous 2 Total removal/
xanthochromic
Lateral ventricular
lesion
3 53/F Headache, dizziness Right cerebellar Meningothelial 1 Total removal/
xanthochromic
No lesion
Figure 2. (A) Angiomatous meningioma with abundant stromal hyalinized vessels, HEx20. (B) CD34 immunoreactivity highlights vascular
network in angiomatous meningioma, x20. (C) Gadolinium-enhanced T1-weighted MRI showed a cystic tumor in the right falx region and left
lateral ventricular lesion in the second case
Figure 3. (A,B) Gadolinium-enhanced T1-weighted MRI showed a homogeneously enhancing solid mass attached to the undersurface of the
tentorium with a large cyst72 • March 2011 • Gulhane Med J Göçmen et al.
cyst formation occurs secondary to central degeneration (16). Cushing has stated that xanthochromic fluid
appears to form at the periphery of the tumors where coalescence forms fairly large cavities with no evidence of adjacent tumor degeneration (23). The cyst
may produce a mass as large as the meningioma itself
(23). In several instances, the expansion of the cyst
rather than the tumor is responsible for the increased
mass effect and clinical deterioration (23). Fortuna
et al. have theorized that intratumoral cysts are the
outcome of cystic degeneration or ischemic necrosis
or hemorrhage within the tumor and this may be in
addition to a secretory function of the tumor (1). The
pathophysiological mechanisms in the formation of
meningioma cysts are ischemic central necrosis and
cystic degeneration, an intratumoral hemorrhage with
subsequent cystic/necrotic changes, the active secretion of fluid by functional tumor cells into the tumor,
glial proliferation as a response to the presence of a
tumor with the elaboration of fluid by glial cells, the
evolution of peritumoral edema into a peritumoral
cyst,and the loculation of cerebrospinal fluid.
The current World Health Organization (WHO)
classifies meningiomas into many different subtypes
based on histological parameters. Of these subtypes,
transitional, fibroblastic, and meningothelial are the
most common ones (27). Most of the meningiomas
are benign neoplasms with a WHO grade 1 classification. Approximately 8% of meningiomas are considered “atypical” (WHO grade 2) and tend to have
a higher incidence of recurrence (28). Anaplastic
meningiomas (WHO grade 3) account for <1% of all
meningiomas and have a much shorter mean survival time, with a 5-year-survival rate of approximately
64%, compared with 95% for atypical meningiomas
(28). The most frequent location of cystic meningiomas is the cerebral convexity followed by the parasagittal region (2,29). Only 1 to 2% of intracranial meningiomas are located in the lateral ventricles (30).
In our cases, the mean age was 62 years and all patients were female. The presenting clinical symptoms
in patients with cystic meningiomas include headaches, seizures, focal neurological deficits, memory loss,
dizziness, aphasia, and personality changes. Cerebral
angiograms were performed in three patients, particularly for differential diagnosis of hemangioblastoma.
Meningotheliomatous meningioma has been reported
as the most common histological type, followed by
transitional and fibroblastic types. Histopathologically,
there were two meningothelial and one angiomatous.
One case was in the posterior fossa, one was in the falx
region and one was on parasagittal region in our series.
The third case is very rare localization of cystic meningioma (31). Second lesions are an extremely rare
condition with cystic meningiomas. According to the
Pubmed search, all the cystic meningiomas did not
have any concomitant lesions.
Recognition of the diagnostic features of cystic meningiomas is important because they may mimic glial
or metastatic tumors with cystic or necrotic changes,
neuroblastoma, or hemangioblastoma (1,10,11,25).
According to Fortuna et al. only 38% of the cases subjected to CT scan were correctly preoperatively diagnosed (1). Coronal CT scans and MRI (sagittal and
coronal scans) have proved very useful in displaying
the solid enhancing nodule attached to the dura.
Multiplanar MRI studies of cystic meningioma have a
diagnostic accuracy of 80% (6). Most cystic meningiomas are located at the cerebral convexity, particularly
in the frontoparietal region (8). Angiographic findings
of meningiomatous vascularization from external carotid arteries can further clarify the preoperative diagnosis (8). MRI scans showed small low signal intensity
areas within the mass lesions on T1-weighted images
and high signal intensity areas on T2-weighted images. The solid components of the mass lesions showed
isointensity, hypointensity, and mixed signal intensity on T1-weighted images and isointensity, hyperintensity, and mixed signal intensity on T2-weighted
images. A MRI shows the presence of a dural attachment, extra-axial location, and cerebral edema better
than CT. Demonstration of the thickening of the dura
(dural tail) with MRI is sometimes a useful clue for the
preoperative diagnosis of a cystic meningioma (18).
However improved imaging techniques can not eliminate diagnostic confusion between cystic meningiomas and some other intracranial tumors (18).
A total excision of the tumor infiltrating cystic
walls is important to prevent a recurrence. Ruelle et
al. suggest that tumoral cyst walls are neoplastic but
peritumoral cyst walls contain gliotic proliferation
(26). Rengachary et al. reported that extratumoral
cyst walls consist of brain parenchyma with glial cell
proliferation as confirmed by the presence of glial fibrillary acidic protein (20). Umansky et al. recommended total removal of the tumor, including the cyst
walls, because complete excision of the cyst walls will
minimize the incidence of recurrence of these benign
tumors (32). We believe when the solid tumor has no
capsule against the cyst, and it is advisable to remove
the cyst because it may contain neoplastic cells.
In conclusion, an unusual site, including lateral
ventricle, intraparenchymal or in the posterior fossa may be also characteristic of cystic meningiomas.
Careful analysis of the imaging studies, primarily
MRI, frequently offers additional information, detec-Volume 53 • Issue 1 Cystic meningiomas • 73
ting the imaging findings that are suggestive of other
disease processes. Cystic meningiomas have a very
low incidence and the cyst wall should be completely
removed to prevent tumor recurrences.