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cystic_meningioma

Cystic meningioma

Cystic meningioma is a rare form of intracranial meningioma. Meningiomas are typically solid tumors but may rarely have cystic components. The diagnosis of cystic meningioma is clinically challenging as the finding of multiple intra-axial tumors, including metastatic tumors, is relatively common.

The term cystic meningioma is applied to both meningiomas with intratumoral degenerative cyst formation as well as those with peritumoral arachnoid cysts or reactive intraparenchymal cysts.

They should not be confused with microcystic meningiomas, a distinct variant, in which the cysts are microscopic.

Epidemiology

Meningiomas are uncommonly associated with cysts and account for 1.6–10% of intracranial meningiomas 1) 2) 3)

Those with more numerous smaller peripheral cysts are more frequent (8-23% of cases). They are over-represented in male patients and the paediatric population

Clinical presentation

Patients present clinically in the same way as patients with non-cystic meningiomas, with either symptoms related to increased intracranial pressure (ICP), focal neurology, or seizures.

Pathology

Various mechanisms have been proposed, and probably more than one is applicable depending on the location of the cysts:

degeneration or necrosis

direct secretion by meningioma

reactive changes (peripheral arachnoid cysts)

Classification

Nauta et al. divided cystic meningiomas into four subtypes according to the location of the cyst with respect to the brain and meningioma

type 1: intratumoral cyst(s), located centrally within the meningioma

type 2: intratumoral cyst(s), situated peripherally within the meningioma but still surrounded by tumour

type 3: cyst(s) located within the adjacent brain

type 4: cyst(s) located between the meningioma and brain (arachnoid cyst)

Diagnosis

Cystic meningioma is not easy to diagnose preoperatively and is often misdiagnosed as a cystic glioma or metastatic brain tumor.

The tumour itself has imaging features identical to non-cystic meningiomas (see the meningioma main article for a full discussion). The cysts are of variable size and can be entirely surrounded by tumour (types 1 or 2) or clearly between the tumour and the brain (type 4) or within the adjacent brain (type 3). On imaging, it is sometimes difficult to distinguish between these types.

Differential diagnosis

The differential is dependent on the location of the tumour. For tumours around the base of the skull, cystic schwannomas (e.g. acoustic schwannoma, trigeminal schwannoma) are the main differential, as they share the bright contrast enhancement, and are commonly cystic when large.


CT whole-brain perfusion (CTP). 4D-CTA showed the arterial supply feeding the tumor and late enhancement of the tumor nodule, similar to that seen in meningioma by conventional angiography. CTP showed that the tumor had a higher cerebral blood flow and cerebral blood volume and a longer mean transit time than adjacent brain tissue. These findings were consistent with meningioma and reinforced the other imaging findings, resulting in the correct preoperative diagnosis. The new techniques available for 320-row CT can potentially be used to improve differential diagnosis and preoperative assessment of cystic tumors with nodules 4).

Case series

A retrospective analysis of 13 patients (mean age: 49.9 years) who underwent surgical resection of intracranial cystic meningiomas from January 2006 to February 2014. There were 5 male and 8 female patients. The Glasgow Outcome Scale was used to assess the clinical outcome at 6 months. Results. Headache was the main presenting clinical feature. Most of the tumours were located on the right side. The frontal convexity was the most common site. Gross total resection was performed in 10 patients. The most common histopathological type was meningothelial variety. Conclusion. Intracranial cystic meningiomas are usually benign that occur in relatively young patients. Resection of cysts that show contrast enhancement is essential to reduce recurrence 5).


Ramanathan et al. report a case of cystic meningioma initially diagnosed as a metastatic tumor from a recurrence of acute lymphoid leukemia. However, postoperative histopathological examination demonstrated an atypical meningioma 6).

1)
Forutuna A, Ferrante L, Acqui M, Guglielmi G, Mastronardi L. Cystic meningiomas. Acta Neurochir (Wien) 1998;90:23–30.
2)
Jain R. Perfusion CT imaging of brain tumors: an overview. AJNR Am J Neuroradiol. 2011;32:1570–1577.
3)
Kremer S, Grand S, Remy C, Pasquir B, Benabid AL, Bracard S, Le Bas JF. Contribution of dynamic contrast MR imaging to the differentiation between dural metastasis and meningioma. Neuroradiol. 2004;46:642–648.
4)
Tabuchi S, Nakajima S. Usefulness of 320-row area detector computed tomography for the diagnosis of cystic falx meningioma. Case Rep Oncol. 2013 Jul 6;6(2):362-6. doi: 10.1159/000353929. Print 2013 May. PubMed PMID: 23898282; PubMed Central PMCID: PMC3724135.
5)
Ghani E, Al-Yamany M. Intracranial cystic meningiomas: A rare type of tumours. Br J Neurosurg. 2015 Jan 24:1-5. [Epub ahead of print] PubMed PMID: 25619978.
6)
Ramanathan N, Kamaruddin KA, Othman A, Mustafa F, Awang MS. Cystic Meningioma Masquerading as a Metastatic Tumor: A Case Report. Malays J Med Sci. 2016 May;23(3):92-4. PubMed PMID: 27418876; PubMed Central PMCID: PMC4934725.
cystic_meningioma.txt · Last modified: 2017/08/23 10:44 by administrador