Cystic meningioma

A.Prof Frank Gaillard et al.

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. 

True cystic meningiomas (type 1 and 2 - see below) are those with a few large central cysts and are uncommon. 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 1

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. 

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

This classification was initially proposed by Nauta et al in 1979, which was later modified by Worthington et al4 in 1985, which at the time of writing (July 2016) is most widely used classification.

Nauta et al. divided cystic meningiomas into four subtypes according to the location of the cyst with respect to the brain and meningioma 3:

  • 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 wall may contain nest of tumor cells.
  • type 4: cyst(s) located within the adjacent brain
  • type 5: cyst(s) located between the meningioma and brain (arachnoid cyst)

4th type is most common.

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. 

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. 

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Article information

rID: 1192
Section: Pathology
Synonyms or Alternate Spellings:
  • Cystic meningiomas

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Cases and figures

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    Case 1: type 1
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    Case 2: type 1 or 2
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    Case 3: type 2 or 3
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    Meningioma T1 gad
    Case 4: type 4
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    Case 5: type 5
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