Management and Diagnosis Challenges in Cystic Meningioma. A Case Report and Review of Literature

Background: Cystic meningioma is a rare variety of meningioma. It represents 4% to 7% of all meningiomas. The authors report a case of intracranial cystic meningioma with a review of literature. Case Report: A 59-year-old female presented with a history of headache followed by left side hemiplegia. CT scan and MRI of the brain showed a right parietal tumor with double solid and cystic components thought to be pilocytic astrocytoma or metastasis preoperatively. At surgery, the extraaxial solid and cystic lesion had a well defined capsule that could be easily separated from the perilesional cortical surface. The tumor was totally removed and the cyst was punctioned. The histological study showed a cystic meningioma WHO Grade I. A follow-up at 10 months after surgery, the patient was going well and recovered from the hemiplegiaa. Conclusion: Cystic meningioma is an uncommon tumor that should be considered in the differential diagnosis of brain tumors with a cystic component. The preoperative diagnosis and management could be in some cases challenging.

disturbance [4] [5] [6]. Preoperatively, the diagnosis of cystic meningioma may pose a dilemma especially in cases based exclusively on CT imaging. Although there are less dilemmas with MRI, cystic menangiomat can easily be misdiagnosed (in about 20% of cases) particularly as glial tumour, metastasis, neuroblastoma or haemangioblastoma [7]. Surgical removal of the entire tumor and its cyst remains the predominant treatment for cystic meningioma [5] [6]. We report here a rare case of intracranial cystic meningioma, and review the importance of preoperative diagnosis as well as the management and perprocedure challenges.

Case Report
A 59-year-old female presented to our Department with a 5-months history of headaches followed by left side hemiplegia over the previous 3 months preceding her admission. Other than hypertension, the patient did not present a significant medical or surgical history.

Investigations
First, a CT scan was performed. On unenhanced images, a large, complex, peripheral mass located in the right frontoparietal region was found ( Figure 1).
Hypodense cystic components were depicted in an otherwise isodense mass.
After iodinated contrast injection, an intense enhancement of the solid component as well as a perilesional oedema was noted. Glioma, metastasis and meningioma were retained in the differential diagnosis. Brain MRI showed a right frontoparietal extraaxial tumor with double solid and cystic components thought to be pylocytic astrocytoma or metastasis preoperatively (Figure 2

Management
The patient underwent general anaesthesia. A large right fronto-parietal craniotomy was performed and the dural plane was opened around the implantation of the lesion. The solid and cystic lesion had a well defined capsule that could be easily separated from the perilesional cortical surface. The tumor was totally reduced using an aspirator and then dissected near the cerebral parenchyma respecting its pial plane after the dirty yellow cyst was carefuly punctioned (Figure 3(a)). A complete excision of the lesion was carried out ( Figure 3(b)) after whicha dural plasty was performed to cover the meningeal defect of the tumour implantation. The histolopathological study showed a cystic meningioma ( Figure 5(a) and Figure 5(b)).

Outcome and Follow-Up
The postoperative outcome was favourable with less recovery of neurological deficit. The control CT scan excluded surgical complication such as haemorrhage and confirm our SIMPSON I resection ( Figure 4). The patient was discharged 10 days after surgery without neurological impairment and physiotherapy was prescribed. Ten months after the surgery, the patient was going well and recovered from the hemiplegia.
The most common site for the appearance of cystic meningiomas is the cerebral convexity, particularly the frontal and parietal lobes, while the cerebral falx is the second most frequent location [10]. In addition, cystic meningiomas can also be identified in the cerebellopontine angle, olfactory groove, suprasellar, falx and   thinning [15]. In a study by Goldsher et al. (1990), three criteria were proposed for the definition of the tail: presence on at least two consecutive images, greatest thickness next to the tumour with tapering away from it and enhancement greater than the tumour itself [16]. Although multiplanar reconstruction on CT or MRI may differentiate extra-axial from intra-axial tumours, a meningioma can mimic an intra-axial lesion when invaginating in the brain [17]. MRI remains the optimal diagnostic means for the diagnosis of cystic meningioma,  [20]. Nauta (1979) classified cystic meningiomas into four types (Table 1) [21]. In Type 1, the cystic component is entirely contained within the tumour and centrally located. In Type 2, the cyst is wholly intratumoural but peripherally located and encapsulated by tumour cells. In Type 3, the cyst is peripherally located and lies in the adjacent parenchyma while in Type 4, the cyst is limited to the interface between the tumour and the brain as loculation of the CSF in the subarachnoid space, so it is not located in the tumour nor in the cerebral parenchyma [21]. Jung et al. [8] added Type V as a mixed type of meningioma combining Types I and III.
In our case, the cystic meningioma was Type 1 (Figure 2(a) and Figure 2(b)).
In addition, El-Fiki et al. (1996) correlated the location of the cyst and its content and also described four types ( peritumoural cysts and small dark brown intratumoural cyst [22]. The use of this classification showed in our case a Type C cystic meningioma (Figure 3(a)).
Moreover, El-Fiki correlated his classification system with Nauta's and noted that Type 1 corresponds to Type C, Type 2 to Type B2, Type 3 to B1 or A2 and Type 4 to A1 (Table 3). In our case, this corelation was found perprocedural.
The differential diagnosis of these lesions depends on the location. For supratentorial masses, high-grade gliomas and metastases have to be included.
In infratentorial lesions, schwannomas with cystic degeneration, metastases and hemangioblastoma in adults and pilocytic astrocytomas in children have to be considered [1].
The diagnosis of meningioma have to be confirmed by histopathological examination in all of the cyst types. In our case, the histological analysis revealed a microcystic meningioma World Health Organization (WHO) grade I ( Figure   5(a) and Figure 5(b)). Although there is no significant correlation between cyst formation and any particular histological type [23], Weber et al. (2003) found a correlation between peritumoural cystic meningiomas and atypical histological types [24].

Conclusion
Cystic meningiomas are rare forms of meningiomas that do not show  These tumours can be easily misdiagnosed as metastases, gliomas and hemangioblastomas macroscopically in CT or MRI. Histopathological diagnosis is always required to confirm the diagnosis of meningioma. The outcome and follow up is generally favorable and good.

Conflicts of Interest
The authors have not any conflict interest in this case report and any financial resources.