Juniper Publishers- Open Access Journal of Case Studies
Cystic Meningioma : A Case Report with a Literature Review
Authored by Mohamed Lahkim
Abstract
Background: Meningiomas are the most common tumors of the central nervous system. However, the cystic form is very rare with an incidence less than 10% and can be confused with other tumors. Authors report a case of intracranial cystic meningioma with a review of literature.
Case report: A 62-year-old female presented headaches resistant to usual analgesics with behavior disorders. Cerebral CT scan showed a right frontal extra-axial tumor with firm and cystic component. Brain MRI provided more details and evoked the diagnosis. The surgery removed the entire tumor. Histological study confirmed a meningothelial cystic meningioma.
Conclusion: Cystic meningioma is an uncommon tumor that should not be omitted from the differential diagnosis of brain tumors with a cystic component and which clinical, radiological, histological and therapeutic features are discussed.
Keywords:Cystic; Meningioma; MRI; Histology
Case Presentation
A 62-year-old female with no pathological history, presented 3 months ago headaches resistant to usual analgesics with behavior disorders. Symptoms worsened with an onset of vomiting, without sensory-motor deficit or seizures. Neurological examination revealed an isolated frontal syndrome.
The cerebral CT scan showed a voluminous intracranial mass, of a right frontal extra-axial seat, well limited, widely in contact with the cranial vault, of a heterogeneous density with a double fleshy and cystic component associated to a peri-lesional edema and a large mass effect on the midline (Figure 1). To better characterize this process a brain MRI was performed. It showed an infiltration of the bone beside the process with an intensely enhanced firm portion after Gadolinium injection and a hypersignal of the fluid component on T2 weighted sequences; as well as a peri-lesional cerebral edema and a subfalcine herniation (Figure 2a & 2b). The diagnosis of cystic meningioma was evoked.
The presence of a concomitant cyst in meningiomas is a source of confusion with other processes such as glioma, hemangioblastoma and metastatic tumors. The leading radiological features allowing the differenciation of those entities are the intense enhancement of the firm portion in contrast to cystic meningiomas at the opposite of lower grade gliomas. The dural attach is a key of diagnosis well identified on enhanced T1- weighted sequences at brain MRI. Furthermore, meningiomas are of an axtra-axial seat while other cystic tumors are not, including hemangioblastoma which is localised in posterior cerebral fossa and rarely extents beyond the cerebellopontine angle [1]. Otherwise, perilesionnel oedema, barely proeminent in typical meningiomas, can not be used as a differencial tool as it is also found in cystic ones.
The neurosurgeon chose a total excision of the tumor with its wall. Symptoms disappeared post-operatively. Histological analysis showed meningothelial cell ranges with oval nuclei and fine chromatin surrounded by fibrous tissue diagnosed as a WHO grade I meningothelial meningioma (Figure 3a & 3b).
The postoerative outcome was quickly favorable with the cessation of vomiting and the disappeareance of headaches. The control CT-scan showed only a residual cavity (Figure 4). The postoperative follow-up currently of 2 years is still favorable.
Discussion
Cystic meningioma is an unusual histological variety of intracranial tumors. It is more frequent on children, representing 12%-24% of their meningiomas while it’s only of 2%-4% on adult [2]. It occurs between 30-60 years old, twice more on female probably due to hormonal factors. Its pathogenesis remains unknown ; several factors were involved in the formation of the cyst as tumor necrosis, cystic degenerescence or intratumoral bleeding [2,3].
Cystic meningioma can occur in all cerebral locations but the most frequent are those of the convexity and the parasagittal region [4]. Symptoms are of a wide variety depending mainly on the site of the tumor but their clinical expression is generally shorter than in firm tumors due to cyst development.
CT interpretation of cystic form is more difficult, arises less than 40% preoperatively unlike the solid form where it has a sensibility of 100% and a specify of 90%. It can be confused with other tumors like gliomas and metastases. Brain MRI is highly efficient and sensitive up to 80%, by showing the characteristic dural attachment, the interface cyst-tumor and the normal brain parenchyma. Nauta et al. [5] classify these tumors according to the location of the cyst relative to the tumor into four types. Type I is a meningioma where intratumoral cyst is central, type 2 where the cyst is intratumoral but peripheral, type 3 with a peritumoral cyst in adjacent brain parenchyma and in type 4 the cyst is peritumoral between the tumor and the adjacent parenchyma.
Histologically, these tumors are of an extreme microscopic diversity. There were many trials to classify them, the most recent of which is the WHO classification of 2000 [6]. It includes 3 grades of increasing aggressivity. Grade I , being and the most frequent, is characterised by elongated cells forming a lobular architecture organised in whorls, surrounded by fibrous tissue with weak mitoses and possible pleomorphic nuclei. It has nine subtypes depending on the architectural layout. Meningothelial, fibroblastic and transitional subtypes are by far the most common. Our case corresponds to a WHO grade I meningothelial cystic meningioma.
Meningioma prognosis and therapeutic management depend on several factors such as histological type, location, age and associated comorbidities. Total excision of the cyst and its wall is a major recommendation to prevent and minimize the risk of recurrence.
Learning Point
i. Cystic meningiomas are rare tumors classified in four types according to the location of the cyst in relation to the firm portion.
ii. They can be confused with other intracranial processes but their main radiological features are the intense enhancement of the fleshy portion, the axtra-axial seat and the dural attach.
iii. Altough brain MRI is effective for preoperative diagnosis, its specficity does not rise to more than 80% and the anatomophological examination is the only tool to provide a certain diagnosis and to determine the histological type of which grade I benign is the most common.
iv. The therapeutic management, often surgical, must privilege a total resection as much as possible. Written informed consent was obtained from the patient for publication of this case report, including accompanying images.
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