Intraventricular meningioma

Intraventricular meningiomas are uncommon compared to the more usual extra axial counterparts (see meningioma).  They can comprise between 0.5 - 2% of intracranial meningiomas. Despite its overall rarity it is one of the commonest adult neoplastic masses in the intraventricular artial location ⁴.

Epidemiology

Most present between the fourth to the sixth decades of life ³. There is a recognised female predilection with the M:F ratio of  ≈ 1:2 ⁴

Location

They are most frequently (80%) seen at the trigone of the lateral ventricles and for reasons that are not clear, slightly more frequently on the left. Considering the distribution of meningiomas, the intraventricular location is comparatively commoner in children ( 20 % of paediatric meningiomas)

• 80% trigone of lateral ventricle
• 15% third ventricle
• 5% fourth ventricle

Radiographic features

Their signal and attenuation characteristics are the same as other meningiomas, demonstrating essentially isodensity and intensity to grey matter precontrast and vivid, usually homogenous enhancement following administration of contrast. Compared to extra axial meningiomas, a greater proportion are calcified (~ 50% c.f. 20% for standard meningioma)

Differential diagnoses

The differential somewhat depends on location. When at the trigone:

• glial tumour
  • ependymoma
  • astrocytoma
• choroid plexus metastasis
• choroid plexus papilloma (particularly in children)

Also see

List of intraventricular neoplasms and lesions