Intraventricular masses (an approach)
Updates to Article Attributes
The ventricular system of the brain plays host to a variety of unique tumours, as well as tumours more frequently seen elsewhere (e.g. meningiomas). In additionBesides, some intra-axial (parenchymal) masses can be mostly exophytic and thus appearing mostly intraventricular. A systematic approach taking into account location, patient demographic and imaging appearances can often substantially narrow the differential, and in most cases suggest one diagnosis as by far the most likely. This is especially important if the mass is benign and can be safely ignored / observed/observed.
Intraventricular masses
The main lesions to be considered are:
- tumours
- cysts
- colloid cyst
- intraventricular simple cysts (including arachnoid cysts, ependymal cysts and large choroid plexus cysts)
- choroid plexus xanthogranuloma
- cavum septum pellucidum
- cavum vergae
- cavum velum interpositum
- infection
- intraventricular haemorrhage
In addition parenchymal lesions which can be periventricular should also be considered, such as:
- glioblastoma
- primary CNS lymphoma
- cerebral metastases
- medulloblastoma / sPNET
- haemangioblastoma
- pilocytic astrocytoma
- atypical teratoid / rhabdoid tumour
- pineal region masses
Imaging
As is the case with most intracranial pathology, MRI is the modality of choice for assessment of intraventricular masses, although CT and DSA both have roles to play. Transcranial ultrasound is particularly useful in infants.
A typical MRI protocol would include three plane imaging (essential if the relationship of the mass to the ventricle is to be confidently determined) and post contrast-contrast studies (the pattern of enhancement is particularly useful in distinguishing a number ofsome the aforementioned lesionslesions mentioned above).
Approach
Aunt Minnie lesions
Perhaps more so than in most other regions of the brain, there are a number ofmany intraventricular masses which have very characteristic appearances, and offer little in the way of a realistic differential diagnosis (or at most between two lesions whichthat are difficult to distinguish on imaging). These can be considered Aunt Minnies and the only way to approach them is to be familiar with their appearance. Example of such lesions include:
- colloid cyst
- intraventricular simple cysts
- choroid plexus xanthogranuloma
- cavum septum pellucidum
- cavum vergae
- cavum velum interpositum
- subependymal giant cell astrocytoma / subependymal hamartomas of tuberous sclerosis
- central neurocytoma
Intraventricular vividly enhancing mass
Finding a vividly enhancing mass in the ventricular system has a limited differential, including:
-
choroid plexus papilloma
- peak incidence: young children
- location: typically in the trigone of children and fourth ventricle of adults
- associated with hydrocephalus
- highly lobulated
- extremely vividly enhancing
- choroid plexus carcinoma can appear identical although usually there is evidence of heterogeneity (necrosis / haemorrhage) and brain invasion
-
intraventricular meningioma
- peak incidence: middle age to older adults
- location: 85% in trigone of the lateral ventricle
- solid and well circumscribed and rounded / spherical or with a few large lobulations
- homogeneous signal intensity
- moderate restricted diffusion
-
heavydense calcification is characteristic
-
ependymoma
- peak incidence: children and young adults
- location: typically on the floor of 4th ventricle in children
- enhancement heterogeneous
- haemorrhage common
- metastasis
- peak incidence: usually older patients
- location: choroid plexus or anywhere with the ventricles
- heterogeneous
- often multiple lesions
-
haemangioblastoma (not intraventricular, but can mimic an intraventricular mass)
- peak incidence: young adults
- location: posterior fossa
- cystic component
- large flow voids
-<p>The ventricular system of the brain plays host to a variety of unique tumours, as well as tumours more frequently seen elsewhere (e.g. meningiomas). In addition some intra-axial (parenchymal) masses can be mostly exophytic and thus appearing mostly intraventricular. A systematic approach taking into account location, patient demographic and imaging appearances can often substantially narrow the differential, and in most cases suggest one diagnosis as by far the most likely. This is especially important if the mass is benign and can be safely ignored / observed. </p><h4>Intraventricular masses</h4><p>The main lesions to be considered are:</p><ul>- +<p>The ventricular system of the brain plays host to a variety of unique tumours, as well as tumours more frequently seen elsewhere (e.g. meningiomas). Besides, some intra-axial (parenchymal) masses can be mostly exophytic and thus appearing mostly intraventricular. A systematic approach taking into account location, patient demographic and imaging appearances can often substantially narrow the differential, and in most cases suggest one diagnosis as by far the most likely. This is especially important if the mass is benign and can be safely ignored/observed. </p><h4>Intraventricular masses</h4><p>The main lesions to be considered are:</p><ul>
-</ul><h4>Imaging</h4><p>As is the case with most intracranial pathology, MRI is the modality of choice for assessment of intraventricular masses, although CT and DSA both have roles to play. Transcranial ultrasound is particularly useful in infants. </p><p>A typical MRI protocol would include three plane imaging (essential if the relationship of the mass to the ventricle is to be confidently determined) and post contrast studies (the pattern of enhancement is particularly useful in distinguishing a number of the aforementioned lesions). </p><h4>Approach</h4><h5>Aunt Minnie lesions</h5><p>Perhaps more so than in most other regions of the brain, there are a number of intraventricular masses which have very characteristic appearances, and offer little in the way of a realistic differential diagnosis (or at most between two lesions which are difficult to distinguish on imaging). These can be considered <a href="/articles/aunt-minnie">Aunt Minnies</a> and the only way to approach them is to be familiar with their appearance. Example of such lesions include:</p><ul>- +</ul><h4>Imaging</h4><p>As is the case with most intracranial pathology, MRI is the modality of choice for assessment of intraventricular masses, although CT and DSA both have roles to play. Transcranial ultrasound is particularly useful in infants. </p><p>A typical MRI protocol would include three plane imaging (essential if the relationship of the mass to the ventricle is to be confidently determined) and post-contrast studies (the pattern of enhancement is particularly useful in distinguishing some the lesions mentioned above). </p><h4>Approach</h4><h5>Aunt Minnie lesions</h5><p>Perhaps more so than in most other regions of the brain, many intraventricular masses have very characteristic appearances, and offer little in the way of a realistic differential diagnosis (or at most between two lesions that are difficult to distinguish on imaging). These can be considered <a href="/articles/aunt-minnie">Aunt Minnies</a> and the only way to approach them is to be familiar with their appearance. Example of such lesions include:</p><ul>
-<li>location: 85% in trigone of lateral ventricle</li>- +<li>location: 85% in trigone of the lateral ventricle</li>
-<li>heavy calcification is characteristic</li>- +<li>dense calcification is characteristic</li>
-<li>location: typically floor of 4th ventricle in children</li>- +<li>location: typically on the floor of 4th ventricle in children</li>
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